diff --git a/.taskcluster.yml b/.taskcluster.yml
index 5bef41d7d97406..d120d54d3960f1 100644
--- a/.taskcluster.yml
+++ b/.taskcluster.yml
@@ -57,7 +57,7 @@ tasks:
             owner: ${owner}
             source: ${event.repository.clone_url}
           payload:
-            image: ghcr.io/web-platform-tests/wpt:2
+            image: ghcr.io/web-platform-tests/wpt:3
             maxRunTime: 7200
             artifacts:
               public/results:
diff --git a/core-aam/attribute/aria-autocomplete.tentative.html b/core-aam/attribute/aria-autocomplete.tentative.html
new file mode 100644
index 00000000000000..b83dcf5b1c2ebd
--- /dev/null
+++ b/core-aam/attribute/aria-autocomplete.tentative.html
@@ -0,0 +1,133 @@
+<!doctype html>
+<meta charset=utf-8>
+<html>
+<head>
+  <title>aria-braillelabel</title>
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+  <script src="/resources/testdriver.js"></script>
+  <script src="/resources/testdriver-vendor.js"></script>
+  <script src="/resources/testdriver-actions.js"></script>
+  <script src="/core-aam/scripts/aam-utils.js"></script>
+</head>
+<body>
+
+<p>
+  This test is marked tentative because it uses an experimental testing API
+  that is presently under development.
+</p>
+
+<input role='combobox' id='test1' aria-autocomplete='both'>
+<input role='combobox' id='test2' aria-autocomplete='inline'>
+<input role='combobox' id='test3' aria-autocomplete='list'>
+
+<script>
+  AAMUtils.verifyAPI(
+    'input[role=combobox][aria-autocomplete=both]',
+    'test1',
+    {
+      "Atspi" : [
+        [
+          "property",
+          "objectAttributes",
+          "contains",
+          "autocomplete:both"
+        ],
+        [
+          "property",
+          "states",
+          "contains",
+          "STATE_SUPPORTS_AUTOCOMPLETION"
+        ]
+      ],
+      "IAccessible2" : [
+         [
+           "property",
+           "objectAttributes",
+           "contains",
+           "autocomplete:both"
+         ],
+         [
+           "property",
+           "states",
+           "contains",
+           "IA2_STATE_SUPPORTS_AUTOCOMPLETION"
+         ]
+      ]
+    }
+  );
+
+  AAMUtils.verifyAPI(
+    'input[role=combobox][aria-autocomplete=inline]',
+    'test2',
+    {
+      "Atspi" : [
+        [
+          "property",
+          "objectAttributes",
+          "contains",
+          "autocomplete:inline"
+        ],
+        [
+          "property",
+          "states",
+          "contains",
+          "STATE_SUPPORTS_AUTOCOMPLETION"
+        ]
+      ],
+      "IAccessible2" : [
+         [
+           "property",
+           "objectAttributes",
+           "contains",
+           "autocomplete:inline"
+         ],
+         [
+           "property",
+           "states",
+           "contains",
+           "IA2_STATE_SUPPORTS_AUTOCOMPLETION"
+         ]
+      ]
+    }
+  );
+
+  AAMUtils.verifyAPI(
+    'input[role=combobox][aria-autocomplete=list]',
+    'test3',
+    {
+      "Atspi" : [
+        [
+          "property",
+          "objectAttributes",
+          "contains",
+          "autocomplete:list"
+        ],
+        [
+          "property",
+          "states",
+          "contains",
+          "STATE_SUPPORTS_AUTOCOMPLETION"
+        ]
+      ],
+      "IAccessible2" : [
+         [
+           "property",
+           "objectAttributes",
+           "contains",
+           "autocomplete:list"
+         ],
+         [
+           "property",
+           "states",
+           "contains",
+           "IA2_STATE_SUPPORTS_AUTOCOMPLETION"
+         ]
+      ]
+    }
+  );
+
+</script>
+
+</body>
+</html>
diff --git a/core-aam/attribute/aria-braillelabel.tentative.html b/core-aam/attribute/aria-braillelabel.tentative.html
new file mode 100644
index 00000000000000..3e4e76c7d8fbae
--- /dev/null
+++ b/core-aam/attribute/aria-braillelabel.tentative.html
@@ -0,0 +1,64 @@
+<!doctype html>
+<meta charset=utf-8>
+<html>
+<head>
+  <title>aria-braillelabel</title>
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+  <script src="/resources/testdriver.js"></script>
+  <script src="/resources/testdriver-vendor.js"></script>
+  <script src="/resources/testdriver-actions.js"></script>
+  <script src="/core-aam/scripts/aam-utils.js"></script>
+</head>
+<body>
+
+<p>
+  This test is marked tentative because it uses an experimental testing API
+  that is presently under development.
+</p>
+
+<button id=test aria-braillelabel=foobar>
+
+<script>
+  AAMUtils.verifyAPI(
+    'button[aria-braillelabel=foobar]',
+    'test',
+    {
+      "Atspi" : [
+        [
+          "property",
+          "objectAttributes",
+          "contains",
+          "braillelabel:foobar"
+        ]
+      ],
+      "AXAPI" : [
+        [
+          "property",
+          "AXBrailleLabel",
+          "is",
+          "foobar"
+        ]
+      ],
+      "IAccessible2" : [
+        [
+          "property",
+          "objectAttributes",
+          "contains",
+          "braillelabel:foobar"
+        ]
+      ],
+      "UIA" : [
+        [
+          "property",
+          "AriaProperties.braillelabel",
+          "is",
+          "foobar"
+        ]
+      ]
+    },
+  );
+</script>
+
+</body>
+</html>
diff --git a/core-aam/attribute/aria-errormessage.tentative.html b/core-aam/attribute/aria-errormessage.tentative.html
new file mode 100644
index 00000000000000..5f9fa57d1a40a9
--- /dev/null
+++ b/core-aam/attribute/aria-errormessage.tentative.html
@@ -0,0 +1,78 @@
+<!doctype html>
+<meta charset=utf-8>
+<html>
+<head>
+  <title>aria-errormessage</title>
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+  <script src="/resources/testdriver.js"></script>
+  <script src="/resources/testdriver-vendor.js"></script>
+  <script src="/resources/testdriver-actions.js"></script>
+  <script src="/core-aam/scripts/aam-utils.js"></script>
+</head>
+<body>
+
+<p>
+  This test is marked tentative because it uses an experimental testing API
+  that is presently under development.
+</p>
+
+<div role='checkbox' id='test' aria-errormessage='error1 error2' aria-invalid='true'>content</div>
+<div id='error1'>hello</div>
+<div id='error2'>world</div>
+
+<script>
+  AAMUtils.verifyAPI(
+    "div[role=checkbox][aria-errormessage='error1 error2'][aria-invalid='true']",
+    'test',
+    {
+      "Atspi" : [
+        [
+          "relation",
+          "RELATION_ERROR_MESSAGE",
+          "is",
+          ['error1', 'error2']
+        ],
+        [
+          "reverseRelation",
+          "RELATION_ERROR_FOR",
+          "is",
+          ['error1', 'error2']
+        ]
+      ],
+      "AXAPI" : [
+        [
+          "property",
+          "AXErrorMessageElements",
+          "is",
+          ['error1', 'error2']
+        ]
+      ],
+      "IAccessible2" : [
+        [
+          "relation",
+          "IA2_RELATION_ERROR",
+          "is",
+          ['error1', 'error2']
+        ],
+        [
+          "reverseRelation",
+          "IA2_RELATION_ERROR_FOR",
+          "is",
+          ['error1', 'error2']
+        ]
+      ],
+      "UIA" : [
+        [
+          "property",
+          "ControllerFor",
+          "is",
+          ['error1', 'error2']
+        ]
+      ]
+    }
+  );
+</script>
+
+</body>
+</html>
diff --git a/core-aam/role/blockquote.tentative.html b/core-aam/role/blockquote.tentative.html
new file mode 100644
index 00000000000000..873cdaacf86f18
--- /dev/null
+++ b/core-aam/role/blockquote.tentative.html
@@ -0,0 +1,82 @@
+<!doctype html>
+<meta charset=utf-8>
+<html>
+<head>
+  <title>role blockquote</title>
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+  <script src="/resources/testdriver.js"></script>
+  <script src="/resources/testdriver-vendor.js"></script>
+  <script src="/resources/testdriver-actions.js"></script>
+  <script src="/core-aam/scripts/aam-utils.js"></script>
+</head>
+<body>
+
+<p>
+  This test is marked tentative because it uses an experimental testing API
+  that is presently under development.
+</p>
+
+<div id=test role=blockquote>quote</div>
+
+<script>
+  AAMUtils.verifyAPI(
+    'div[role=blockquote]',
+    'test',
+    {
+      "Atspi" : [
+         [
+            "property",
+            "role",
+            "is",
+            "block quote"
+         ]
+      ],
+      "AXAPI" : [
+         [
+            "property",
+            "AXRole",
+            "is",
+            "AXGroup"
+         ],
+         [
+            "property",
+            "AXSubrole",
+            "is",
+            "<nil>"
+         ]
+      ],
+      "IAccessible2" : [
+         [
+            "property",
+            "role",
+            "is",
+            "IA2_ROLE_BLOCK_QUOTE"
+         ],
+         [
+            "property",
+            "msaaRole",
+            "is",
+            "ROLE_SYSTEM_GROUPING"
+         ]
+      ],
+      "UIA" : [
+         [
+            "property",
+            "ControlType",
+            "is",
+            "Group"
+         ],
+         [
+            "property",
+            "LocalizedControlType",
+            "is",
+            "blockquote"
+         ]
+      ]
+    }
+  );
+</script>
+
+</body>
+</html>
diff --git a/core-aam/role/button_with_default_values_for_aria-pressed_and_aria-haspopup.tentative.html b/core-aam/role/button_with_default_values_for_aria-pressed_and_aria-haspopup.tentative.html
new file mode 100644
index 00000000000000..9f8fe5ed5bbfcc
--- /dev/null
+++ b/core-aam/role/button_with_default_values_for_aria-pressed_and_aria-haspopup.tentative.html
@@ -0,0 +1,76 @@
+<!doctype html>
+<meta charset=utf-8>
+<html>
+<head>
+  <title>role button with default values for aria-pressed and aria-hapopup</title>
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+  <script src="/resources/testdriver.js"></script>
+  <script src="/resources/testdriver-vendor.js"></script>
+  <script src="/resources/testdriver-actions.js"></script>
+  <script src="/core-aam/scripts/aam-utils.js"></script>
+</head>
+<body>
+
+<p>
+  This test is marked tentative because it uses an experimental testing API
+  that is presently under development.
+</p>
+
+<div id=test1 role=button>click me</div>
+<div id=test2 role=button aria-pressed>click me</div>
+<div id=test3 role=button aria-pressed aria-haspopup>click me</div>
+<div id=test4 role=button aria-haspopup>click me</div>
+<div id=test5 role=button aria-haspopup=false>click me</div>
+
+<script>
+  var test_statements = {
+    "Atspi" : [
+       [
+          "property",
+          "role",
+          "is",
+          "push button"
+       ]
+    ],
+    "AXAPI" : [
+       [
+          "property",
+          "AXRole",
+          "is",
+          "AXButton"
+       ],
+       [
+          "property",
+          "AXSubrole",
+          "is",
+          "<nil>"
+       ]
+    ],
+    "IAccessible2" : [
+       [
+          "property",
+          "msaaRole",
+          "is",
+          "ROLE_SYSTEM_PUSHBUTTON"
+       ]
+    ],
+    "UIA" : [
+       [
+          "property",
+          "ControlType",
+          "is",
+          "Button"
+       ]
+    ]
+  };
+
+  AAMUtils.verifyAPI('div[role="button"]', 'test1', test_statements);
+  AAMUtils.verifyAPI('div[role="button"][aria-pressed]', 'test2', test_statements);
+  AAMUtils.verifyAPI('div[role="button"][aria-pressed][aria-haspopup]', 'test3', test_statements);
+  AAMUtils.verifyAPI('div[role="button"][aria-haspopup]', 'test4', test_statements);
+  AAMUtils.verifyAPI('div[role="button"][aria-haspopup="false"]', 'test5', test_statements);
+</script>
+
+</body>
+</html>
diff --git a/core-aam/role/button_with_defined_value_for_aria-pressed.tentative.html b/core-aam/role/button_with_defined_value_for_aria-pressed.tentative.html
new file mode 100644
index 00000000000000..85e7cb78c94eb8
--- /dev/null
+++ b/core-aam/role/button_with_defined_value_for_aria-pressed.tentative.html
@@ -0,0 +1,73 @@
+<!doctype html>
+<meta charset=utf-8>
+<html>
+<head>
+  <title>role button with defined value for aria-pressed</title>
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+  <script src="/resources/testdriver.js"></script>
+  <script src="/resources/testdriver-vendor.js"></script>
+  <script src="/resources/testdriver-actions.js"></script>
+  <script src="/core-aam/scripts/aam-utils.js"></script>
+</head>
+<body>
+<p>
+  This test is marked tentative because it uses an experimental testing API
+  that is presently under development.
+</p>
+
+<div id=test1 role=button aria-pressed=true>press me</div>
+<div id=test2 role=button aria-pressed=false>press me</div>
+
+<script>
+  var test_statements = {
+    "Atspi" : [
+       [
+          "property",
+          "role",
+          "is",
+          "toggle button"
+       ]
+    ],
+    "AXAPI" : [
+       [
+          "property",
+          "AXRole",
+          "is",
+          "AXCheckBox"
+       ],
+       [
+          "property",
+          "AXSubrole",
+          "is",
+          "AXToggle"
+       ]
+    ],
+    "IAccessible2" : [
+       [
+          "property",
+          "role",
+          "is",
+          "IA2_ROLE_TOGGLE_BUTTON"
+       ],
+      [
+          "property",
+          "msaaRole",
+          "is",
+          "ROLE_SYSTEM_PUSHBUTTON"
+       ]
+    ],
+    "UIA" : [
+       [
+          "property",
+          "ControlType",
+          "is",
+          "Button"
+       ]
+    ]
+  };
+
+  AAMUtils.verifyAPI('div[role="button"][aria-pressed="true"]', 'test1', test_statements);
+  AAMUtils.verifyAPI('div[role="button"][aria-pressed="false"]','test2', test_statements);
+</script>
+</body>
diff --git a/core-aam/role/button_with_non_false_value_for_aria-haspopup.tentative.html b/core-aam/role/button_with_non_false_value_for_aria-haspopup.tentative.html
new file mode 100644
index 00000000000000..7dfec7bdd76665
--- /dev/null
+++ b/core-aam/role/button_with_non_false_value_for_aria-haspopup.tentative.html
@@ -0,0 +1,114 @@
+<!doctype html>
+<meta charset=utf-8>
+<html>
+<head>
+  <title>role button with non false value for aria-pressed</title>
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+  <script src="/resources/testdriver.js"></script>
+  <script src="/resources/testdriver-vendor.js"></script>
+  <script src="/resources/testdriver-actions.js"></script>
+  <script src="/core-aam/scripts/aam-utils.js"></script>
+</head>
+<body>
+
+<p>
+  This test is marked tentative because it uses an experimental testing API
+  that is presently under development.
+</p>
+
+<div id=test1 role=button aria-haspopup=true>click me</div>
+<div id=test2 role=button aria-haspopup=menu>click me</div>
+<div id=test3 role=button aria-haspopup=listbox>click me</div>
+<div id=test4 role=button aria-haspopup=tree>click me</div>
+<div id=test5 role=button aria-haspopup=grid>click me</div>
+<div id=test6 role=button aria-haspopup=dialog>click me</div>
+
+<script>
+  var test_statements =  {
+     "Atspi" : [
+        [
+           "property",
+           "role",
+           "is",
+           "push button"
+        ]
+     ],
+     "AXAPI" : [
+        [
+           "property",
+           "AXRole",
+           "is",
+           "AXPopUpButton"
+        ],
+        [
+           "property",
+           "AXSubrole",
+           "is",
+           "<nil>"
+        ],
+        [
+           "property",
+           "actions",
+           "contains",
+           "AXShowMenu"
+        ]
+     ],
+     "IAccessible2" : [
+        [
+           "property",
+           "msaaRole",
+           "is",
+           "ROLE_SYSTEM_PUSHBUTTON"
+        ]
+     ],
+     "UIA" : [
+        [
+           "property",
+           "ControlType",
+           "is",
+           "Button"
+        ]
+     ]
+  };
+
+
+
+  AAMUtils.verifyAPI(
+    'div[role="button"][aria-haspopup="true"]',
+    'test1',
+    test_statements
+  );
+
+  AAMUtils.verifyAPI(
+    'div[role="button"][aria-haspopup="menu"]',
+    'test2',
+    test_statements
+  );
+
+  AAMUtils.verifyAPI(
+    'div[role="button"][aria-haspopup="listbox"]',
+    'test3',
+    test_statements
+  );
+
+  AAMUtils.verifyAPI(
+    'div[role="button"][aria-haspopup="tree"]',
+    'test4',
+    test_statements
+  );
+
+  AAMUtils.verifyAPI(
+    'div[role="button"][aria-haspopup="grid"]',
+    'test5',
+    test_statements
+  );
+
+  AAMUtils.verifyAPI(
+    'div[role="button"][aria-haspopup="dialog"]',
+    'test6',
+    test_statements
+  );
+
+</script>
+</body>
diff --git a/core-aam/scripts/aam-utils.js b/core-aam/scripts/aam-utils.js
new file mode 100644
index 00000000000000..6118aa992e8b7c
--- /dev/null
+++ b/core-aam/scripts/aam-utils.js
@@ -0,0 +1,54 @@
+/*
+  Utility files for platform specific accessibility API tests for the
+  Accessibility API Mappings (AAM) standards: Core-AAM and HTML-aam
+*/
+
+const AAMUtils = {
+  APIS: ['Atspi', 'AXAPI', 'IAccessible2', 'UIA'],
+
+  runAssertions: function(test_statements, results) {
+    // If the test was not run, the API doesn't apply to backend OS,
+    // pass with no asserts.
+    if (!results) {
+      return;
+    }
+
+    if (results.length !== test_statements.length) {
+      assert_unreached(`Recieved a different number of results than test statements: ${results}`);
+    }
+
+    for (let i = 0; i < results.length; i++) {
+      assert_equals(results[i], "Pass", `${test_statements[i].join(' ')}`)
+    }
+  },
+
+
+  /*
+    Creates a subtest for each API. Runs no asserts for APIs not found.
+
+    test_name: name of the test
+    id:        id of element to test the accessibility node of
+    map:       map of APIs to lists of test statements
+  */
+
+  verifyAPI: function(test_name, id, map) {
+    if (!map) {
+      throw "Error: missing accessibility API test map";
+    }
+
+    for (const api of this.APIS) {
+      if (map[api] && map[api].length) {
+        promise_test(async t => {
+          let results = await test_driver.test_accessibility_api(
+            id,
+            map[api],
+            api
+          );
+
+          this.runAssertions(map[api], results);
+
+        }, `api: ${api}, ${test_name}`);
+      }
+    }
+  }
+}
diff --git a/resources/testdriver.js b/resources/testdriver.js
index 0986b207696568..78f6df7eb15d0f 100644
--- a/resources/testdriver.js
+++ b/resources/testdriver.js
@@ -2307,6 +2307,23 @@
          */
         uninstall_web_extension: function(extension_id) {
             return window.test_driver_internal.uninstall_web_extension(extension_id);
+        },
+
+        /**
+         * Test properties of API's accessibility node. This test API endpoint
+         * is still under development and subject to change, and for now should
+         * only be used for /core-aam and /html-aam tests.
+         *
+         * @param {id}         id of element
+         * @param {test}       list of test statements
+         * @param {api}        string indicating the API to test
+         * @returns {Promise}  The string "match" when the test succeeds,
+         *                     a failure message otherwise
+         */
+        test_accessibility_api: async function(dom_id, test, api) {
+            return window.test_driver_internal.test_accessibility_api(
+                dom_id, test, api, location.href
+            );
         }
     };
 
@@ -2644,6 +2661,11 @@
 
         async get_global_privacy_control() {
             throw new Error("get_global_privacy_control() is not implemented by testdriver-vendor.js");
+        },
+
+        async test_accessibility_api(dom_id, test, api, url) {
+            throw new Error("test_accessibility_api() is not available.");
         }
+
     };
 })();
diff --git a/tools/ci/tc/tasks/test.yml b/tools/ci/tc/tasks/test.yml
index daa86a629f2924..e28eb22f160576 100644
--- a/tools/ci/tc/tasks/test.yml
+++ b/tools/ci/tc/tasks/test.yml
@@ -4,7 +4,7 @@ components:
     workerType: ci
     schedulerId: taskcluster-github
     deadline: "24 hours"
-    image: ghcr.io/web-platform-tests/wpt:2
+    image: ghcr.io/web-platform-tests/wpt:3
     maxRunTime: 7200
     artifacts:
       public/results:
diff --git a/tools/docker/Dockerfile b/tools/docker/Dockerfile
index a936ad9167f058..53f1c9f3d7a5be 100644
--- a/tools/docker/Dockerfile
+++ b/tools/docker/Dockerfile
@@ -20,6 +20,9 @@ RUN apt-get -qqy update \
     glib-networking-services \
     gstreamer1.0-plugins-bad \
     gstreamer1.0-gl \
+    libatspi2.0-dev \
+    libcairo2-dev \
+    libgirepository1.0-dev \
     libosmesa6-dev \
     libproxy1-plugin-webkit \
     libvirt-daemon-system \
diff --git a/tools/mypy.ini b/tools/mypy.ini
index 22259b03aab751..9dffef7433eccf 100644
--- a/tools/mypy.ini
+++ b/tools/mypy.ini
@@ -42,6 +42,9 @@ follow_imports = silent
 follow_imports = silent
 
 # Ignore missing or untyped libraries.
+[mypy-ApplicationServices.*]
+ignore_missing_imports = True
+
 [mypy-Cocoa.*]
 ignore_missing_imports = True
 
@@ -51,6 +54,12 @@ ignore_missing_imports = True
 [mypy-Quartz.*]
 ignore_missing_imports = True
 
+[mypy-comtypes.*]
+ignore_missing_imports = True
+
+[mypy-gi.*]
+ignore_missing_imports = True
+
 [mypy-marionette_driver.*]
 ignore_missing_imports = True
 
diff --git a/tools/wpt/run.py b/tools/wpt/run.py
index 0f35fb5e68c877..d645a6932e8544 100644
--- a/tools/wpt/run.py
+++ b/tools/wpt/run.py
@@ -327,6 +327,10 @@ def setup_kwargs(self, kwargs):
         if kwargs["browser_channel"] == "nightly" and kwargs["enable_webtransport_h3"] is None:
             kwargs["enable_webtransport_h3"] = True
 
+        if kwargs["enable_accessibility_api"]:
+            kwargs["extra_prefs"].append("accessibility.force_disabled=-1")
+
+
         # Turn off Firefox WebRTC ICE logging on WPT (turned on by mozrunner)
         safe_unsetenv('R_LOG_LEVEL')
         safe_unsetenv('R_LOG_DESTINATION')
@@ -520,7 +524,10 @@ def setup_kwargs(self, kwargs):
             # We are on Taskcluster, where our Docker container does not have
             # enough capabilities to run Chrome with sandboxing. (gh-20133)
             kwargs["binary_args"].append("--no-sandbox")
-
+        if kwargs["enable_accessibility_api"]:
+            # Necessary to force chrome to register in AT-SPI2.
+            os.environ["ACCESSIBILITY_ENABLED"] = "1"
+            kwargs["binary_args"].append("--force-renderer-accessibility")
 
 class HeadlessShell(BrowserSetup):
     name = "headless_shell"
@@ -942,6 +949,10 @@ def setup_wptrunner(venv, **kwargs):
     if not venv.skip_virtualenv_setup:
         requirements = [os.path.join(wpt_root, "tools", "wptrunner", "requirements.txt")]
         requirements.extend(setup_cls.requirements())
+
+        if kwargs["enable_accessibility_api"]:
+            requirements.append(os.path.join(wpt_root, "tools", "wptrunner", "requirements_platform_accessibility.txt"))
+
         venv.install_requirements(*requirements)
 
     affected_revish = kwargs.get("affected")
diff --git a/tools/wptrunner/requirements_platform_accessibility.txt b/tools/wptrunner/requirements_platform_accessibility.txt
new file mode 100644
index 00000000000000..b14331f7e25e93
--- /dev/null
+++ b/tools/wptrunner/requirements_platform_accessibility.txt
@@ -0,0 +1,8 @@
+comtypes==1.4.11; sys_platform == 'win32'
+PyGObject==3.50.1; sys_platform == 'linux' and python_version >= '3.9'
+PyGObject==3.48.2; sys_platform == 'linux' and python_version < '3.9'
+pyobjc-framework-Accessibility==11.1; sys_platform == 'darwin' and python_version >= '3.9'
+pyobjc-framework-ApplicationServices==11.1; sys_platform == 'darwin' and python_version >= '3.9'
+pyobjc==10.3.2; sys_platform == 'darwin' and python_version < '3.9'
+pyobjc-framework-Accessibility==10.3.2; sys_platform == 'darwin' and python_version < '3.9'
+pyobjc-framework-ApplicationServices==10.3.2; sys_platform == 'darwin' and python_version < '3.9'
diff --git a/tools/wptrunner/wptrunner/executors/actions.py b/tools/wptrunner/wptrunner/executors/actions.py
index 785962062822bf..1c336f1ff9854d 100644
--- a/tools/wptrunner/wptrunner/executors/actions.py
+++ b/tools/wptrunner/wptrunner/executors/actions.py
@@ -594,6 +594,21 @@ def __call__(self, payload):
         extension_id = payload["extension_id"]
         return self.protocol.web_extensions.uninstall_web_extension(extension_id)
 
+class TestAccessibilityAPIAction:
+    name = "test_accessibility_api"
+
+    def __init__(self, logger, protocol):
+        self.logger = logger
+        self.protocol = protocol
+
+    def __call__(self, payload):
+        dom_id = payload["dom_id"]
+        test = payload["test"]
+        api = payload["api"]
+        url = payload["url"]
+        return self.protocol.platform_accessibility.test_accessibility_api(dom_id, test, api, url)
+
+
 actions = [ClickAction,
            DeleteAllCookiesAction,
            GetAllCookiesAction,
@@ -640,4 +655,5 @@ def __call__(self, payload):
            GetGlobalPrivacyControlAction,
            SetGlobalPrivacyControlAction,
            WebExtensionInstallAction,
-           WebExtensionUninstallAction]
+           WebExtensionUninstallAction,
+           TestAccessibilityAPIAction]
diff --git a/tools/wptrunner/wptrunner/executors/base.py b/tools/wptrunner/wptrunner/executors/base.py
index dd10aca589c72f..870985295c2628 100644
--- a/tools/wptrunner/wptrunner/executors/base.py
+++ b/tools/wptrunner/wptrunner/executors/base.py
@@ -771,6 +771,9 @@ def _run(self):
             self.result_flag.set()
 
 
+class PlatformAccessibilityNotEnabled(Exception):
+    pass
+
 class CallbackHandler:
     """Handle callbacks from testdriver-using tests.
 
@@ -830,6 +833,12 @@ def process_action(self, url, payload):
         except self.unimplemented_exc:
             self.logger.warning("Action %s not implemented" % action)
             self._send_message(cmd_id, "complete", "error", f"Action {action} not implemented")
+        except PlatformAccessibilityNotEnabled:
+            self.logger.warning(
+                f"Action {action} failed: platform accessibility testing is not enabled. Try --enable-platform-accessibility",
+                exc_info=True
+            )
+            self._send_message(cmd_id, "complete", "error", f"Action {action} failed, platform accessibliity testing not enabled.")
         except self.expected_exc as e:
             self.logger.debug(f"Action {action} failed with an expected exception", exc_info=True)
             self._send_message(cmd_id, "complete", "error", f"Action {action} failed: {e!s}")
diff --git a/tools/wptrunner/wptrunner/executors/executormarionette.py b/tools/wptrunner/wptrunner/executors/executormarionette.py
index e1b954a7d23da5..2012af80e08e37 100644
--- a/tools/wptrunner/wptrunner/executors/executormarionette.py
+++ b/tools/wptrunner/wptrunner/executors/executormarionette.py
@@ -51,6 +51,7 @@
                        WindowProtocolPart,
                        merge_dicts)
 
+from .executorplatformaccessibility import PlatformAccessibilityProtocolPart
 
 def do_delayed_imports():
     global errors, marionette, Addons, WebAuthn
@@ -827,12 +828,14 @@ class MarionetteProtocol(Protocol):
                   MarionetteDevicePostureProtocolPart,
                   MarionetteVirtualPressureSourceProtocolPart,
                   MarionetteDisplayFeaturesProtocolPart,
-                  MarionetteWebExtensionsProtocolPart]
+                  MarionetteWebExtensionsProtocolPart,
+                  PlatformAccessibilityProtocolPart]
 
     def __init__(self, executor, browser, capabilities=None, timeout_multiplier=1, e10s=True, ccov=False):
         do_delayed_imports()
 
         super().__init__(executor, browser)
+        self.product_name = browser.product_name
         self.marionette = None
         self.marionette_port = browser.marionette_port
         self.capabilities = capabilities
diff --git a/tools/wptrunner/wptrunner/executors/executorplatformaccessibility.py b/tools/wptrunner/wptrunner/executors/executorplatformaccessibility.py
new file mode 100644
index 00000000000000..7dcf5e921ee1af
--- /dev/null
+++ b/tools/wptrunner/wptrunner/executors/executorplatformaccessibility.py
@@ -0,0 +1,98 @@
+from __future__ import annotations
+
+from sys import platform
+from typing import List, Optional, Protocol, Union
+
+from mozlog.structuredlog import StructuredLogger
+
+from .base import PlatformAccessibilityNotEnabled
+from .protocol import ProtocolPart
+
+
+class PlatformAccessibilityExecutorImpl(Protocol):
+    """Protocol defining the interface for platform accessibility executors."""
+
+    def setup(self, product_name: str, logger: StructuredLogger) -> None:
+        ...
+
+    def test_accessibility_api(
+        self, dom_id: str, test: List[List[str]], api: str, url: str
+    ) -> List[str]:
+        ...
+
+
+def valid_api_for_platform(api: str) -> bool:
+    if platform == "linux" and api == "Atspi":
+        return True
+    if platform == "darwin" and api == "AXAPI":
+        return True
+    if platform == "win32" and (api == "UIA" or api == "IAccessible2"):
+        return True
+    return False
+
+
+class PlatformAccessibilityProtocolPart(ProtocolPart):
+    """Protocol part for platform accessibility introspection"""
+
+    name = "platform_accessibility"
+
+    def setup(self) -> None:
+        self.product_name: str = self.parent.product_name
+        self.impl: Optional[PlatformAccessibilityExecutorImpl] = None
+        self.__init_platform_executor()
+
+    def __init_platform_executor(self) -> None:
+        if platform == "linux":
+            try:
+                from .platformaccessibility.executoratspi import AtspiExecutorImpl
+            except ModuleNotFoundError:
+                self.logger.warning(
+                    "Accessibility API testing was not enabled, accessibility API tests will fail."
+                )
+                return
+
+            self.impl = AtspiExecutorImpl()
+            self.impl.setup(self.product_name, self.logger)
+
+        if platform == "darwin":
+            try:
+                from .platformaccessibility.executoraxapi import AXAPIExecutorImpl
+            except ModuleNotFoundError:
+                self.logger.warning(
+                    "Accessibility API testing was not enabled, accessibility API tests will fail."
+                )
+                return
+
+            self.impl = AXAPIExecutorImpl()
+            self.impl.setup(self.product_name, self.logger)
+
+        if platform == "win32":
+            try:
+                from .platformaccessibility.executorwindowsaccessibility import (
+                    WindowsAccessibilityExecutorImpl,
+                )
+            except ModuleNotFoundError:
+                self.logger.warning(
+                    "Accessibility API testing was not enabled, accessibility API tests will fail."
+                )
+                return
+
+            self.impl = WindowsAccessibilityExecutorImpl()
+            self.impl.setup(self.product_name, self.logger)
+
+    def test_accessibility_api(
+        self, dom_id: str, test: List[List[str]], api: str, url: str
+    ) -> Union[str, List[str]]:
+        # Tests will pass if they are not applicable for a platform,
+        # for example, Windows API tests passed to Linux. Ideally, this will
+        # be fixed with a "not applicable".
+        if not valid_api_for_platform(api):
+            return ""
+
+        # self.impl will not exist ifo --enable-accessibility-api was not included
+        # or the necessary python requirements for accessibility API tests have not
+        # been installed.
+        if not self.impl:
+            raise PlatformAccessibilityNotEnabled()
+
+        return self.impl.test_accessibility_api(dom_id, test, api, url)
diff --git a/tools/wptrunner/wptrunner/executors/executorwebdriver.py b/tools/wptrunner/wptrunner/executors/executorwebdriver.py
index f7f4428b2c604c..92c696c13fda0f 100644
--- a/tools/wptrunner/wptrunner/executors/executorwebdriver.py
+++ b/tools/wptrunner/wptrunner/executors/executorwebdriver.py
@@ -52,6 +52,8 @@
                        WebExtensionsProtocolPart,
                        merge_dicts)
 
+from .executorplatformaccessibility import PlatformAccessibilityProtocolPart
+
 from typing import Any, List, Dict, Optional
 from webdriver.client import Session
 from webdriver import error as webdriver_error
@@ -1029,10 +1031,12 @@ class WebDriverProtocol(Protocol):
                   WebDriverProtectedAudienceProtocolPart,
                   WebDriverDisplayFeaturesProtocolPart,
                   WebDriverGlobalPrivacyControlProtocolPart,
-                  WebDriverWebExtensionsProtocolPart]
+                  WebDriverWebExtensionsProtocolPart,
+                  PlatformAccessibilityProtocolPart]
 
     def __init__(self, executor, browser, capabilities, **kwargs):
         super().__init__(executor, browser)
+        self.product_name = browser.product_name
         self.capabilities = capabilities
         if hasattr(browser, "capabilities"):
             if self.capabilities is None:
diff --git a/tools/wptrunner/wptrunner/executors/platformaccessibility/__init__.py b/tools/wptrunner/wptrunner/executors/platformaccessibility/__init__.py
new file mode 100644
index 00000000000000..e69de29bb2d1d6
diff --git a/tools/wptrunner/wptrunner/executors/platformaccessibility/executoratspi.py b/tools/wptrunner/wptrunner/executors/platformaccessibility/executoratspi.py
new file mode 100644
index 00000000000000..080d6204f893e6
--- /dev/null
+++ b/tools/wptrunner/wptrunner/executors/platformaccessibility/executoratspi.py
@@ -0,0 +1,368 @@
+from __future__ import annotations
+
+import time
+from typing import Optional, List, Dict, Any
+
+import gi
+
+gi.require_version("Atspi", "2.0")
+from gi.repository import Atspi
+
+from mozlog.structuredlog import StructuredLogger
+
+
+def poll_for_tab(root: Atspi.Accessible, product: str, url: str) -> Atspi.Accessible:
+    """Poll until the tab with the test url is loaded and available in the
+       accessibility API. Assumes wptrunner has already started a browser
+       process and navigated to the test page.
+
+    :param root: The node in the accessibility API representing the browser process.
+    :param product: The name of the browser.
+    :param url: The url of the test.
+    :return: Atspi.Accessible representing test document.
+    """
+
+    tab = find_tab(root, product, url)
+    while not tab:
+        time.sleep(0.01)
+        tab = find_tab(root, product, url)
+
+    return tab
+
+
+def find_tab(
+    root: Atspi.Accessible, product: str, url: str
+) -> Optional[Atspi.Accessible]:
+    """Find the tab with the test url.
+
+    :param root: The node in the accessibility API representing the browser process.
+    :param product: The name of the browser.
+    :param url: The url of the test.
+    :return: Atspi.Accessible representing test document or None.
+    """
+
+    stack = [root]
+    while stack:
+        node = stack.pop()
+        if Atspi.Accessible.get_role_name(node) == "frame":
+            relationset = Atspi.Accessible.get_relation_set(node)
+            for relation in relationset:
+                if relation.get_relation_type() == Atspi.RelationType.EMBEDS:
+                    tab = relation.get_target(0)
+                    if is_ready(tab, product, url):
+                        return tab
+                    else:
+                        return None
+            continue
+
+        for i in range(Atspi.Accessible.get_child_count(node)):
+            child = Atspi.Accessible.get_child_at_index(node, i)
+            stack.append(child)
+
+    return None
+
+
+def is_ready(tab: Atspi.Accessible, product: str, url: str) -> bool:
+    """Test whether tab is fully loaded.
+
+    :param tab: Atspi.Accessible representing test document.
+    :param product: The name of the browser.
+    :param url: The url of the test.
+    :return: Boolean.
+    """
+
+    # Firefox uses the "BUSY" state to indicate the page is not ready.
+    if product == "firefox":
+        state_set = Atspi.Accessible.get_state_set(tab)
+        return not Atspi.StateSet.contains(state_set, Atspi.StateType.BUSY)
+
+    # Chromium family browsers do not use "BUSY", but you can
+    # tell if the document can be queried by URL attribute. If the 'URI'
+    # attribute is not here, we need to query for a new accessible object.
+    document = Atspi.Accessible.get_document_iface(tab)
+    document_attributes = Atspi.Document.get_document_attributes(document)
+    return "URI" in document_attributes and document_attributes["URI"] == url
+
+
+def find_browser(name: str) -> Optional[Atspi.Accessible]:
+    """Find the Atspi.Accessible representing the browser.
+
+    :param name: The name of the browser.
+    :return: Atspi.Accessible or None.
+    """
+
+    desktop = Atspi.get_desktop(0)
+    child_count = Atspi.Accessible.get_child_count(desktop)
+    for i in range(child_count):
+        app = Atspi.Accessible.get_child_at_index(desktop, i)
+        full_app_name = Atspi.Accessible.get_name(app)
+        if name in full_app_name.lower():
+            return app
+    return None
+
+
+def find_node(root: Atspi.Accessible, dom_id: str) -> Optional[TestNode]:
+    """Find the Atspi.Accessible with a specified dom_id.
+
+    :dom_id: The dom ID.
+    :return: TestNode or None if not found.
+    """
+
+    stack = [root]
+    while stack:
+        node = stack.pop()
+
+        attributes = Atspi.Accessible.get_attributes(node)
+        if "id" in attributes and attributes["id"] == dom_id:
+            return TestNode(root, dom_id, node)
+
+        for i in range(Atspi.Accessible.get_child_count(node)):
+            child = Atspi.Accessible.get_child_at_index(node, i)
+            stack.append(child)
+
+    return None
+
+
+class AtspiExecutorImpl:
+    def setup(self, product_name: str, logger: StructuredLogger) -> None:
+        """Setup for accessibility API testing.
+
+        :product_name: The name of the browser, used to find the browser in the accessibility API.
+        :logger: Logger for logging errors.
+        """
+        self.logger = logger
+        self.product_name = product_name
+        self.root: Optional[Atspi.Accessible] = None
+        self.document: Optional[Atspi.Accessible] = None
+        self.test_url: Optional[str] = None
+
+        self.root = find_browser(self.product_name)
+        if not self.root:
+            self.logger.warning(
+                f"Couldn't find browser {self.product_name} in accessibility API ATSPI. Accessibility API queries will not succeeded."
+            )
+
+    def __poll_for_tab_if_necessary(self, url: str) -> None:
+        """If accessible node representing the test document for this URL has
+           not been found, find it and set self.document.
+
+        :param url: The url of the test.
+        """
+        if not self.root:
+            raise Exception(
+                f"Couldn't find browser {self.product_name} in accessibility API ATSPI. Did you turn on accessibility?"
+            )
+
+        if self.test_url != url or not self.document:
+            self.test_url = url
+            self.document = poll_for_tab(self.root, self.product_name, url)
+
+    def test_accessibility_api(
+        self, dom_id: str, test: List[List[str]], api: str, url: str
+    ) -> List[str]:
+        """Execute a test of the accessibility API.
+
+        :param dom_id: The dom id of the node to test.
+        :param test: List of test statements.
+        :param api: The API to test.
+        :param url: The url of the test.
+        """
+        self.__poll_for_tab_if_necessary(url)
+
+        test_node = find_node(self.document, dom_id)
+
+        if not test_node:
+            raise Exception(
+                f"Couldn't find node with id {dom_id} in accessibility API ATSPI."
+            )
+        self.logger.debug(
+            f"Found node with id {dom_id} in accessibility API ATSPI: {test_node.serialize()}"
+        )
+
+        results = []
+        for test_statement in test:
+            results.append(test_node.run_test_statement(TestStatement(test_statement)))
+
+        return results
+
+
+class TestNode:
+    """Wrapper around an Atspi Node for testing purposes"""
+
+    def __init__(
+        self, document: Atspi.Accessible, dom_id: str, node: Atspi.Accessible
+    ) -> None:
+        self.document = document
+        self.dom_id = dom_id
+        self.node = node
+
+    def serialize(self) -> Dict[str, Any]:
+        """Convert the node to a dictionary for printing/debugging.
+
+        :returns: A dictionary representing the node.
+        """
+
+        node_dictionary: Dict[str, Any] = {}
+        node_dictionary["API"] = "atspi"
+        node_dictionary["role"] = Atspi.Accessible.get_role_name(self.node)
+        node_dictionary["name"] = Atspi.Accessible.get_name(self.node)
+        node_dictionary["description"] = Atspi.Accessible.get_description(self.node)
+        node_dictionary["states"] = self.get_state_list()
+        node_dictionary["objectAttributes"] = Atspi.Accessible.get_attributes_as_array(
+            self.node
+        )
+        node_dictionary["relations"] = self.get_relations_dictionary()
+
+        return node_dictionary
+
+    def run_test_statement(self, statement: TestStatement) -> str:
+        """Run a single test statement.
+
+        :statement: a TestStatement object
+        :returns: the string "Pass" or a failure message.
+        """
+
+        if statement.type == "property":
+            return self.run_property_test(statement)
+
+        if statement.type == "relation":
+            return self.run_relation_test(statement)
+
+        if statement.type == "reverseRelation":
+            return self.run_reverse_relation_test(statement)
+
+        return "Error: not implemented ({statement.type})"
+
+    def run_property_test(self, statement: TestStatement) -> str:
+        """Run a single test statement with type "property".
+
+        :statement: a TestStatement object
+        :returns: the string "Pass" or a failure message.
+        """
+
+        if statement.key == "role":
+            role = Atspi.Accessible.get_role_name(self.node)
+            return statement.value_compare_with(role)
+
+        if statement.key == "objectAttributes":
+            attributes = Atspi.Accessible.get_attributes_as_array(self.node)
+            return statement.value_contained_or_not_contained_in(attributes)
+
+        if statement.key == "states":
+            states = self.get_state_list()
+            return statement.value_contained_or_not_contained_in(states)
+
+        return f"Fail: not implemented ({statement.key})"
+
+    def run_relation_test(self, statement: TestStatement) -> str:
+        """Run a single test statement with type "relation".
+
+        :statement: a TestStatement object
+        :returns: the string "Pass" or a failure message.
+        """
+
+        expected_relation = statement.key
+        expected_ids = statement.value
+        relations_dict = self.get_relations_dictionary()
+        if expected_relation not in relations_dict:
+            return f"Fail: relation not in list: {list(relations_dict.keys())}"
+
+        id_str = ",".join(relations_dict[expected_relation])
+        expected_id_str = ",".join(expected_ids)
+        if id_str != expected_id_str:
+            return f"Fail: {expected_relation}={relations_dict[expected_relation]}"
+        return "Pass"
+
+    def run_reverse_relation_test(self, statement: TestStatement) -> str:
+        """Run a single test statement with type "reverseRelation".
+
+        :statement: a TestStatement object
+        :returns: the string "Pass" or a failure message.
+        """
+
+        expected_relation = statement.key
+        # statement.value is a list of dom_ids representing the nodes that should have
+        # a reverse relation back to this node.
+        expected_elements = statement.value
+
+        for element in expected_elements:
+            test_node = find_node(self.document, element)
+            if not test_node:
+                return "Fail: element '{element}' could not be found"
+
+            relations_dict = test_node.get_relations_dictionary()
+
+            if expected_relation not in relations_dict:
+                return f"Fail: element '{element}' does not have reverse relation, has relations: {list(relations_dict.keys())}"
+
+            if self.dom_id not in relations_dict[expected_relation]:
+                return f"Fail: element '{element}' {expected_relation}={relations_dict[expected_relation]}"
+
+        return "Pass"
+
+    def get_relations_dictionary(self) -> Dict[str, List[str]]:
+        """
+        :returns: A dictionary with relations as keys and the values, DOM ids.
+        """
+        relations_dict: Dict[str, List[str]] = {}
+        relations = Atspi.Accessible.get_relation_set(self.node)
+        for relation in relations:
+            name = relation.get_relation_type().value_name.removeprefix("ATSPI_")
+            relations_dict[name] = []
+            num_targets = relation.get_n_targets()
+
+            for i in range(num_targets):
+                target = relation.get_target(i)
+                attributes = Atspi.Accessible.get_attributes(target)
+                if "id" in attributes:
+                    relations_dict[name].append(attributes["id"])
+                else:
+                    relations_dict[name].append("[unknown id]")
+
+        return relations_dict
+
+    def get_state_list(self) -> List[str]:
+        """
+        :returns: A list of states for this Atspi.Accessible.
+        """
+        state_list = Atspi.Accessible.get_state_set(self.node).get_states()
+        state_string_list = []
+        for state in state_list:
+            state_string_list.append(state.value_name.replace("ATSPI_", ""))
+        return state_string_list
+
+
+class TestStatement:
+    """Wrapper around an accessibility API test statement"""
+
+    def __init__(self, test_statement_arr: List[str]) -> None:
+        self.test_statement_arr = test_statement_arr
+
+        self.type: str = test_statement_arr[0]
+        self.key: str = test_statement_arr[1]
+        self.assertion: str = test_statement_arr[2]
+        self.value: Any = test_statement_arr[3]
+
+    def value_compare_with(self, value: str) -> str:
+        if self.assertion == "is":
+            if self.value != value:
+                return f"Fail: {self.key} is {value}"
+        elif self.assertion == "isNot":
+            if self.value == value:
+                return f"Fail: {self.key} is {value}"
+        else:
+            return f"Error: Test statement malformed, '{self.assertion}' must be 'is' or 'isNot'."
+
+        return "Pass"
+
+    def value_contained_or_not_contained_in(self, array: List[str]) -> str:
+        if self.assertion == "contains":
+            if self.value not in array:
+                return f"Fail: {array} does not contain {self.value}"
+        elif self.assertion == "doesNotContain":
+            if self.value in array:
+                return f"Fail: {array} contains {self.value}"
+        else:
+            return f"Error: Test statement malformed, '{self.assertion}' must be 'contains' or 'doesNotContain'."
+
+        return "Pass"
diff --git a/tools/wptrunner/wptrunner/executors/platformaccessibility/executoraxapi.py b/tools/wptrunner/wptrunner/executors/platformaccessibility/executoraxapi.py
new file mode 100644
index 00000000000000..710fe6ad962914
--- /dev/null
+++ b/tools/wptrunner/wptrunner/executors/platformaccessibility/executoraxapi.py
@@ -0,0 +1,155 @@
+from typing import Optional, List, Dict, Any
+
+from ApplicationServices import (
+    AXUIElementCopyAttributeNames,
+    AXUIElementCopyAttributeValue,
+    AXUIElementCreateApplication,
+)
+
+from Cocoa import (
+    NSApplicationActivationPolicyRegular,
+    NSPredicate,
+    NSWorkspace,
+)
+
+from mozlog.structuredlog import StructuredLogger
+
+
+def find_browser(name: str) -> Optional[Any]:
+    """Find the AXUIElement representing the browser.
+
+    :param name: The name of the browser.
+    :return: AXUIElement or None.
+    """
+
+    ws = NSWorkspace.sharedWorkspace()
+    regular_predicate = NSPredicate.predicateWithFormat_(
+        f"activationPolicy == {NSApplicationActivationPolicyRegular}"
+    )
+    running_apps = ws.runningApplications().filteredArrayUsingPredicate_(
+        regular_predicate
+    )
+    name_predicate = NSPredicate.predicateWithFormat_(
+        f"localizedName contains[c] '{name}'"
+    )
+    filtered_apps = running_apps.filteredArrayUsingPredicate_(name_predicate)
+    if filtered_apps.count() == 0:
+        return None
+    app = filtered_apps[0]
+    pid = app.processIdentifier()
+    if pid == -1:
+        return None
+    return AXUIElementCreateApplication(pid)
+
+
+def find_active_tab(browser: Any) -> Optional[Any]:
+    """Find the active tab of the browser.
+
+    :param browser: The name of the browser.
+    :return: AXUIElement representing test document or None.
+    """
+
+    stack = [browser]
+    while stack:
+        node = stack.pop()
+
+        err, role = AXUIElementCopyAttributeValue(node, "AXRole", None)
+        if err:
+            continue
+        if role == "AXWebArea":
+            return node
+
+        err, children = AXUIElementCopyAttributeValue(node, "AXChildren", None)
+        if err:
+            continue
+        stack.extend(children)
+
+    return None
+
+
+def find_node(root: Any, attribute: str, expected_value: str) -> Optional[Any]:
+    """Find the AXUIElement with a specified dom_id.
+
+    :dom_id: The dom ID.
+    :return: AXUIElement or None if not found.
+    """
+
+    stack = [root]
+    while stack:
+        node = stack.pop()
+
+        err, attributes = AXUIElementCopyAttributeNames(node, None)
+        if err:
+            continue
+        if attribute in attributes:
+            err, value = AXUIElementCopyAttributeValue(node, attribute, None)
+            if err:
+                continue
+            if value == expected_value:
+                return node
+
+        err, children = AXUIElementCopyAttributeValue(node, "AXChildren", None)
+        if err:
+            continue
+        stack.extend(children)
+    return None
+
+
+def serialize_node(node: Any) -> Dict[str, Any]:
+    """Convert the node to a dictionary for printing/debugging.
+
+    :returns: A dictionary representing the node.
+    """
+    props = {}
+    props["API"] = "axapi"
+    err, role = AXUIElementCopyAttributeValue(node, "AXRole", None)
+    props["role"] = role
+    err, name = AXUIElementCopyAttributeValue(node, "AXTitle", None)
+    props["name"] = name
+    err, description = AXUIElementCopyAttributeValue(node, "AXDescription", None)
+    props["description"] = description
+
+    return props
+
+
+class AXAPIExecutorImpl:
+    def setup(self, product_name: str, logger: StructuredLogger) -> None:
+        """Setup for accessibility API testing.
+
+        :product_name: The name of the browser, used to find the browser in the accessibility API.
+        :logger: Logger for logging errors.
+        """
+        self.product_name = product_name
+        self.logger = logger
+        self.root: Optional[Any] = find_browser(self.product_name)
+
+        if not self.root:
+            self.logger.warning(
+                f"Couldn't find browser {self.product_name} in accessibility API AX API. Accessibility API queries will not succeeded."
+            )
+
+    def test_accessibility_api(
+        self, dom_id: str, test: List[List[str]], api: str, url: str
+    ) -> List[str]:
+        """Execute a test of the accessibility API.
+
+        :param dom_id: The dom id of the node to test.
+        :param test: List of test statements.
+        :param api: The API to test.
+        :param url: The url of the test.
+        """
+        tab = find_active_tab(self.root)
+        node = find_node(tab, "AXDOMIdentifier", dom_id)
+        if not node:
+            raise Exception(
+                f"Couldn't find node with ID {dom_id} in accessibility API AXAPI."
+            )
+        self.logger.debug(
+            f"Found node with id {dom_id} in accessibility API AXAPI: {serialize_node(node)}"
+        )
+
+        results = []
+        for test_statement in test:
+            results.append("Fail: Test not implemented.")
+
+        return results
diff --git a/tools/wptrunner/wptrunner/executors/platformaccessibility/executorwindowsaccessibility.py b/tools/wptrunner/wptrunner/executors/platformaccessibility/executorwindowsaccessibility.py
new file mode 100644
index 00000000000000..303c5781d5f99b
--- /dev/null
+++ b/tools/wptrunner/wptrunner/executors/platformaccessibility/executorwindowsaccessibility.py
@@ -0,0 +1,180 @@
+from __future__ import annotations
+
+import time
+from typing import Any, Dict, List, Optional
+
+import ctypes
+from ctypes import POINTER, byref
+from ctypes.wintypes import BOOL, HWND, LPARAM
+
+# Type aliases for COM interface pointers.
+# These are dynamically generated by comtypes at runtime.
+IAccessiblePtr = Any
+IAccessible2Ptr = Any
+
+import comtypes.client
+from comtypes import IServiceProvider
+
+from mozlog.structuredlog import StructuredLogger
+
+from ..platformaccessibility.ia2.constants import (  # type: ignore[attr-defined]
+    IAccessible2_2,
+    Role,
+    get_msaa_state_list,
+    get_state_list,
+)
+
+CHILDID_SELF = 0
+OBJID_CLIENT = -4
+
+user32 = ctypes.windll.user32  # type: ignore
+oleacc = ctypes.oledll.oleacc  # type: ignore
+oleacc_mod = comtypes.client.GetModule("oleacc.dll")
+IAccessible = oleacc_mod.IAccessible  # noqa: N816
+
+uia_mod = comtypes.client.GetModule("UIAutomationCore.dll")
+uia_client = comtypes.CoCreateInstance(
+    uia_mod.CUIAutomation._reg_clsid_,
+    interface=uia_mod.IUIAutomation,
+    clsctx=comtypes.CLSCTX_INPROC_SERVER,
+)
+
+
+def accessible_object_from_window(hwnd: HWND) -> IAccessiblePtr:
+    p = POINTER(IAccessible)()
+    oleacc.AccessibleObjectFromWindow(
+        hwnd, OBJID_CLIENT, byref(IAccessible._iid_), byref(p)
+    )
+    return p
+
+
+def name_from_hwnd(hwnd: HWND) -> str:
+    MAX_CHARS = 257
+    buffer = ctypes.create_unicode_buffer(MAX_CHARS)
+    user32.GetWindowTextW(hwnd, buffer, MAX_CHARS)
+    return buffer.value
+
+
+def get_browser_hwnd(product_name: str) -> HWND:
+    found: List[HWND] = []
+
+    @ctypes.WINFUNCTYPE(BOOL, HWND, LPARAM)  # type: ignore[attr-defined, misc]
+    def check_window_name(hwnd: HWND, lParam: LPARAM) -> bool:  # noqa: N803
+        window_name = name_from_hwnd(hwnd)
+        if product_name not in window_name.lower():
+            # EnumWindows should continue enumerating
+            return True
+        found.append(hwnd)
+        # EnumWindows should stop enumerating (since we found the right window)
+        return False
+
+    user32.EnumWindows(check_window_name, LPARAM(0))
+    if not found:
+        raise LookupError(f"Couldn't find {product_name} HWND")
+    return found[0]
+
+
+def to_ia2(node: IAccessiblePtr) -> IAccessible2Ptr:
+    service = node.QueryInterface(IServiceProvider)
+    return service.QueryService(IAccessible._iid_, IAccessible2_2)
+
+
+def find_browser(product_name: str) -> IAccessible2Ptr:
+    hwnd = get_browser_hwnd(product_name)
+    root = accessible_object_from_window(hwnd)
+    return to_ia2(root)
+
+
+def poll_for_tab(url: str, root: IAccessible2Ptr) -> IAccessible2Ptr:
+    tab = find_tab(url, root)
+    while not tab:
+        time.sleep(0.01)
+        tab = find_tab(url, root)
+    return tab
+
+
+def find_tab(url: str, root: IAccessible2Ptr) -> Optional[IAccessible2Ptr]:
+    # TODO: Add and use relation constants (IA2_RELATION_EMBEDS).
+    targets, count = root.relationTargetsOfType("embeds", 1)
+    if count >= 1:
+        ia2 = to_ia2(targets[0])
+        if ia2.accValue(CHILDID_SELF) == url:
+            return ia2
+
+    return find_tab_by_searching_tree(url, root)
+
+
+def find_tab_by_searching_tree(url: str, root: IAccessible2Ptr) -> Optional[IAccessible2Ptr]:
+    for i in range(1, root.accChildCount + 1):
+        child = to_ia2(root.accChild(i))
+        if child.accRole(CHILDID_SELF) == Role.ROLE_SYSTEM_DOCUMENT:
+            if child.accValue(CHILDID_SELF) == url:
+                return child
+            # No need to search within documents.
+            return None
+        descendant = find_tab_by_searching_tree(url, child)
+        if descendant:
+            return descendant
+    return None
+
+
+def find_ia2_node(root: IAccessible2Ptr, id: str) -> Optional[IAccessible2Ptr]:
+    id_attribute = f"id:{id};"
+    for i in range(1, root.accChildCount + 1):
+        child = to_ia2(root.accChild(i))
+        if child.attributes and id_attribute in child.attributes:
+            return child
+        descendant = find_ia2_node(child, id)
+        if descendant:
+            return descendant
+    return None
+
+
+def serialize_node(node: IAccessible2Ptr) -> Dict[str, Any]:
+    node_dictionary: Dict[str, Any] = {}
+    node_dictionary["API"] = "windows"
+
+    # MSAA properties
+    node_dictionary["name"] = node.accName(CHILDID_SELF)
+    node_dictionary["msaa_role"] = Role(node.accRole(CHILDID_SELF)).name
+    node_dictionary["msaa_states"] = get_msaa_state_list(node.accState(CHILDID_SELF))
+
+    # IAccessible2 properties
+    node_dictionary["ia2_role"] = Role(node.role()).name
+    node_dictionary["ia2_states"] = get_state_list(node.states)
+
+    return node_dictionary
+
+
+class WindowsAccessibilityExecutorImpl:
+    def setup(self, product_name: str, logger: StructuredLogger) -> None:
+        self.product_name = product_name
+        self.logger = logger
+
+    def test_accessibility_api(
+        self, dom_id: str, test: List[List[str]], api: str, url: str
+    ) -> List[str]:
+        """Execute a test of the accessibility API.
+
+        :param dom_id: The dom id of the node to test.
+        :param test: List of test statements.
+        :param api: The API to test.
+        :param url: The url of the test.
+        """
+        self.root = find_browser(self.product_name)
+        if not self.root:
+            raise Exception(f"Couldn't find browser {self.product_name}.")
+
+        tab = poll_for_tab(url, self.root)
+        node = find_ia2_node(tab, dom_id)
+        if not node:
+            raise Exception(f"Couldn't find node with ID {dom_id}.")
+        self.logger.debug(
+            f"Found node with id {dom_id} in accessibility API IA2: {serialize_node(node)}"
+        )
+
+        results: List[str] = []
+        for test_statement in test:
+            results.append("Fail: Test not implemented.")
+
+        return results
diff --git a/tools/wptrunner/wptrunner/executors/platformaccessibility/ia2/constants.py b/tools/wptrunner/wptrunner/executors/platformaccessibility/ia2/constants.py
new file mode 100644
index 00000000000000..db5c104c6097c8
--- /dev/null
+++ b/tools/wptrunner/wptrunner/executors/platformaccessibility/ia2/constants.py
@@ -0,0 +1,208 @@
+# type: ignore
+
+import enum
+import os
+import comtypes.client
+
+# Get IAccessible2 constants for helper functions below
+ia2_tlb = os.path.join(
+    os.path.dirname(os.path.realpath(__file__)),
+    "ia2_api_all.tlb",
+)
+ia2_mod = comtypes.client.GetModule(ia2_tlb)
+# Add to globals the many IAccessible2 constants. These will also be imported
+# when this file is imported.
+globals().update((k, getattr(ia2_mod, k)) for k in ia2_mod.__all__)
+
+class Role(enum.IntEnum):
+    # MSAA roles - constants not provided via oleacc
+    ROLE_SYSTEM_TITLEBAR = 1
+    ROLE_SYSTEM_MENUBAR = 2
+    ROLE_SYSTEM_SCROLLBAR = 3
+    ROLE_SYSTEM_GRIP = 4
+    ROLE_SYSTEM_SOUND = 5
+    ROLE_SYSTEM_CURSOR = 6
+    ROLE_SYSTEM_CARET = 7
+    ROLE_SYSTEM_ALERT = 8
+    ROLE_SYSTEM_WINDOW = 9
+    ROLE_SYSTEM_CLIENT = 10
+    ROLE_SYSTEM_MENUPOPUP = 11
+    ROLE_SYSTEM_MENUITEM = 12
+    ROLE_SYSTEM_TOOLTIP = 13
+    ROLE_SYSTEM_APPLICATION = 14
+    ROLE_SYSTEM_DOCUMENT = 15
+    ROLE_SYSTEM_PANE = 16
+    ROLE_SYSTEM_CHART = 17
+    ROLE_SYSTEM_DIALOG = 18
+    ROLE_SYSTEM_BORDER = 19
+    ROLE_SYSTEM_GROUPING = 20
+    ROLE_SYSTEM_SEPARATOR = 21
+    ROLE_SYSTEM_TOOLBAR = 22
+    ROLE_SYSTEM_STATUSBAR = 23
+    ROLE_SYSTEM_TABLE = 24
+    ROLE_SYSTEM_COLUMNHEADER = 25
+    ROLE_SYSTEM_ROWHEADER = 26
+    ROLE_SYSTEM_COLUMN = 27
+    ROLE_SYSTEM_ROW = 28
+    ROLE_SYSTEM_CELL = 29
+    ROLE_SYSTEM_LINK = 30
+    ROLE_SYSTEM_HELPBALLOON = 31
+    ROLE_SYSTEM_CHARACTER = 32
+    ROLE_SYSTEM_LIST = 33
+    ROLE_SYSTEM_LISTITEM = 34
+    ROLE_SYSTEM_OUTLINE = 35
+    ROLE_SYSTEM_OUTLINEITEM = 36
+    ROLE_SYSTEM_PAGETAB = 37
+    ROLE_SYSTEM_PROPERTYPAGE = 38
+    ROLE_SYSTEM_INDICATOR = 39
+    ROLE_SYSTEM_GRAPHIC = 40
+    ROLE_SYSTEM_STATICTEXT = 41
+    ROLE_SYSTEM_TEXT = 42
+    ROLE_SYSTEM_PUSHBUTTON = 43
+    ROLE_SYSTEM_CHECKBUTTON = 44
+    ROLE_SYSTEM_RADIOBUTTON = 45
+    ROLE_SYSTEM_COMBOBOX = 46
+    ROLE_SYSTEM_DROPLIST = 47
+    ROLE_SYSTEM_PROGRESSBAR = 48
+    ROLE_SYSTEM_DIAL = 49
+    ROLE_SYSTEM_HOTKEYFIELD = 50
+    ROLE_SYSTEM_SLIDER = 51
+    ROLE_SYSTEM_SPINBUTTON = 52
+    ROLE_SYSTEM_DIAGRAM = 53
+    ROLE_SYSTEM_ANIMATION = 54
+    ROLE_SYSTEM_EQUATION = 55
+    ROLE_SYSTEM_BUTTONDROPDOWN = 56
+    ROLE_SYSTEM_BUTTONMENU = 57
+    ROLE_SYSTEM_BUTTONDROPDOWNGRID = 58
+    ROLE_SYSTEM_WHITESPACE = 59
+    ROLE_SYSTEM_PAGETABLIST = 60
+    ROLE_SYSTEM_CLOCK = 61
+    ROLE_SYSTEM_SPLITBUTTON = 62
+    ROLE_SYSTEM_IPADDRESS = 63
+    ROLE_SYSTEM_OUTLINEBUTTON = 64
+    # IAccessible2 roles
+    IA2_ROLE_CANVAS = ia2_mod.IA2_ROLE_CANVAS
+    IA2_ROLE_CAPTION = ia2_mod.IA2_ROLE_CAPTION
+    IA2_ROLE_CHECK_MENU_ITEM = ia2_mod.IA2_ROLE_CHECK_MENU_ITEM
+    IA2_ROLE_COLOR_CHOOSER = ia2_mod.IA2_ROLE_COLOR_CHOOSER
+    IA2_ROLE_DATE_EDITOR = ia2_mod.IA2_ROLE_DATE_EDITOR
+    IA2_ROLE_DESKTOP_ICON = ia2_mod.IA2_ROLE_DESKTOP_ICON
+    IA2_ROLE_DESKTOP_PANE = ia2_mod.IA2_ROLE_DESKTOP_PANE
+    IA2_ROLE_DIRECTORY_PANE = ia2_mod.IA2_ROLE_DIRECTORY_PANE
+    IA2_ROLE_EDITBAR = ia2_mod.IA2_ROLE_EDITBAR
+    IA2_ROLE_EMBEDDED_OBJECT = ia2_mod.IA2_ROLE_EMBEDDED_OBJECT
+    IA2_ROLE_ENDNOTE = ia2_mod.IA2_ROLE_ENDNOTE
+    IA2_ROLE_FILE_CHOOSER = ia2_mod.IA2_ROLE_FILE_CHOOSER
+    IA2_ROLE_FONT_CHOOSER = ia2_mod.IA2_ROLE_FONT_CHOOSER
+    IA2_ROLE_FOOTER = ia2_mod.IA2_ROLE_FOOTER
+    IA2_ROLE_FOOTNOTE = ia2_mod.IA2_ROLE_FOOTNOTE
+    IA2_ROLE_FORM = ia2_mod.IA2_ROLE_FORM
+    IA2_ROLE_FRAME = ia2_mod.IA2_ROLE_FRAME
+    IA2_ROLE_GLASS_PANE = ia2_mod.IA2_ROLE_GLASS_PANE
+    IA2_ROLE_HEADER = ia2_mod.IA2_ROLE_HEADER
+    IA2_ROLE_HEADING = ia2_mod.IA2_ROLE_HEADING
+    IA2_ROLE_ICON = ia2_mod.IA2_ROLE_ICON
+    IA2_ROLE_IMAGE_MAP = ia2_mod.IA2_ROLE_IMAGE_MAP
+    IA2_ROLE_INPUT_METHOD_WINDOW = ia2_mod.IA2_ROLE_INPUT_METHOD_WINDOW
+    IA2_ROLE_INTERNAL_FRAME = ia2_mod.IA2_ROLE_INTERNAL_FRAME
+    IA2_ROLE_LABEL = ia2_mod.IA2_ROLE_LABEL
+    IA2_ROLE_LAYERED_PANE = ia2_mod.IA2_ROLE_LAYERED_PANE
+    IA2_ROLE_NOTE = ia2_mod.IA2_ROLE_NOTE
+    IA2_ROLE_OPTION_PANE = ia2_mod.IA2_ROLE_OPTION_PANE
+    IA2_ROLE_PAGE = ia2_mod.IA2_ROLE_PAGE
+    IA2_ROLE_PARAGRAPH = ia2_mod.IA2_ROLE_PARAGRAPH
+    IA2_ROLE_RADIO_MENU_ITEM = ia2_mod.IA2_ROLE_RADIO_MENU_ITEM
+    IA2_ROLE_REDUNDANT_OBJECT = ia2_mod.IA2_ROLE_REDUNDANT_OBJECT
+    IA2_ROLE_ROOT_PANE = ia2_mod.IA2_ROLE_ROOT_PANE
+    IA2_ROLE_RULER = ia2_mod.IA2_ROLE_RULER
+    IA2_ROLE_SCROLL_PANE = ia2_mod.IA2_ROLE_SCROLL_PANE
+    IA2_ROLE_SECTION = ia2_mod.IA2_ROLE_SECTION
+    IA2_ROLE_SHAPE = ia2_mod.IA2_ROLE_SHAPE
+    IA2_ROLE_SPLIT_PANE = ia2_mod.IA2_ROLE_SPLIT_PANE
+    IA2_ROLE_TEAR_OFF_MENU = ia2_mod.IA2_ROLE_TEAR_OFF_MENU
+    IA2_ROLE_TERMINAL = ia2_mod.IA2_ROLE_TERMINAL
+    IA2_ROLE_TEXT_FRAME = ia2_mod.IA2_ROLE_TEXT_FRAME
+    IA2_ROLE_TOGGLE_BUTTON = ia2_mod.IA2_ROLE_TOGGLE_BUTTON
+    IA2_ROLE_UNKNOWN = ia2_mod.IA2_ROLE_UNKNOWN
+    IA2_ROLE_VIEW_PORT = ia2_mod.IA2_ROLE_VIEW_PORT
+    IA2_ROLE_COMPLEMENTARY_CONTENT = ia2_mod.IA2_ROLE_COMPLEMENTARY_CONTENT
+    IA2_ROLE_LANDMARK = ia2_mod.IA2_ROLE_LANDMARK
+    IA2_ROLE_LEVEL_BAR = ia2_mod.IA2_ROLE_LEVEL_BAR
+    IA2_ROLE_CONTENT_DELETION = ia2_mod.IA2_ROLE_CONTENT_DELETION
+    IA2_ROLE_CONTENT_INSERTION = ia2_mod.IA2_ROLE_CONTENT_INSERTION
+    IA2_ROLE_BLOCK_QUOTE = ia2_mod.IA2_ROLE_BLOCK_QUOTE
+    IA2_ROLE_MARK = ia2_mod.IA2_ROLE_MARK
+    IA2_ROLE_SUGGESTION = ia2_mod.IA2_ROLE_SUGGESTION
+    IA2_ROLE_COMMENT = ia2_mod.IA2_ROLE_COMMENT
+
+
+class MsaaState(enum.IntFlag):
+    STATE_SYSTEM_UNAVAILABLE = 0x00000001
+    STATE_SYSTEM_SELECTED = 0x00000002
+    STATE_SYSTEM_FOCUSED = 0x00000004
+    STATE_SYSTEM_PRESSED = 0x00000008
+    STATE_SYSTEM_CHECKED = 0x00000010
+    STATE_SYSTEM_MIXED = 0x00000020
+    STATE_SYSTEM_READONLY = 0x00000040
+    STATE_SYSTEM_HOTTRACKED = 0x00000080
+    STATE_SYSTEM_DEFAULT = 0x00000100
+    STATE_SYSTEM_EXPANDED = 0x00000200
+    STATE_SYSTEM_COLLAPSED = 0x00000400
+    STATE_SYSTEM_BUSY = 0x00000800
+    STATE_SYSTEM_FLOATING = 0x00001000
+    STATE_SYSTEM_MARQUEED = 0x00002000
+    STATE_SYSTEM_ANIMATED = 0x00004000
+    STATE_SYSTEM_INVISIBLE = 0x00008000
+    STATE_SYSTEM_OFFSCREEN = 0x00010000
+    STATE_SYSTEM_SIZEABLE = 0x00020000
+    STATE_SYSTEM_MOVEABLE = 0x00040000
+    STATE_SYSTEM_SELFVOICING = 0x00080000
+    STATE_SYSTEM_FOCUSABLE = 0x00100000
+    STATE_SYSTEM_SELECTABLE = 0x00200000
+    STATE_SYSTEM_LINKED = 0x00400000
+    STATE_SYSTEM_TRAVERSED = 0x00800000
+    STATE_SYSTEM_MULTISELECTABLE = 0x01000000
+    STATE_SYSTEM_EXTSELECTABLE = 0x02000000
+    STATE_SYSTEM_ALERT_LOW = 0x04000000
+    STATE_SYSTEM_ALERT_MEDIUM = 0x08000000
+    STATE_SYSTEM_ALERT_HIGH = 0x10000000
+    STATE_SYSTEM_PROTECTED = 0x20000000
+    STATE_SYSTEM_HASPOPUP = 0x40000000
+
+
+class Ia2State(enum.IntFlag):
+    IA2_STATE_ACTIVE = ia2_mod.IA2_STATE_ACTIVE
+    IA2_STATE_ARMED = ia2_mod.IA2_STATE_ARMED
+    IA2_STATE_CHECKABLE = ia2_mod.IA2_STATE_CHECKABLE
+    IA2_STATE_DEFUNCT = ia2_mod.IA2_STATE_DEFUNCT
+    IA2_STATE_EDITABLE = ia2_mod.IA2_STATE_EDITABLE
+    IA2_STATE_HORIZONTAL = ia2_mod.IA2_STATE_HORIZONTAL
+    IA2_STATE_ICONIFIED = ia2_mod.IA2_STATE_ICONIFIED
+    IA2_STATE_INVALID_ENTRY = ia2_mod.IA2_STATE_INVALID_ENTRY
+    IA2_STATE_MANAGES_DESCENDANTS = ia2_mod.IA2_STATE_MANAGES_DESCENDANTS
+    IA2_STATE_MODAL = ia2_mod.IA2_STATE_MODAL
+    IA2_STATE_MULTI_LINE = ia2_mod.IA2_STATE_MULTI_LINE
+    IA2_STATE_OPAQUE = ia2_mod.IA2_STATE_OPAQUE
+    IA2_STATE_PINNED = ia2_mod.IA2_STATE_PINNED
+    IA2_STATE_REQUIRED = ia2_mod.IA2_STATE_REQUIRED
+    IA2_STATE_SELECTABLE_TEXT = ia2_mod.IA2_STATE_SELECTABLE_TEXT
+    IA2_STATE_SINGLE_LINE = ia2_mod.IA2_STATE_SINGLE_LINE
+    IA2_STATE_STALE = ia2_mod.IA2_STATE_STALE
+    IA2_STATE_SUPPORTS_AUTOCOMPLETION = ia2_mod.IA2_STATE_SUPPORTS_AUTOCOMPLETION
+    IA2_STATE_TRANSIENT = ia2_mod.IA2_STATE_TRANSIENT
+    IA2_STATE_VERTICAL = ia2_mod.IA2_STATE_VERTICAL
+
+
+def get_msaa_state_list(states):
+    state_strings = []
+    for state in MsaaState:
+        if states & state:
+            state_strings.append(state.name.replace("STATE_SYSTEM_", ""))
+    return state_strings
+
+def get_state_list(states):
+    state_strings = []
+    for state in Ia2State:
+        if states & state:
+            state_strings.append(state.name.replace("IA2_STATE_", ""))
+    return state_strings
diff --git a/tools/wptrunner/wptrunner/executors/platformaccessibility/ia2/ia2_api_all.tlb b/tools/wptrunner/wptrunner/executors/platformaccessibility/ia2/ia2_api_all.tlb
new file mode 100644
index 00000000000000..449c10b258dd7b
Binary files /dev/null and b/tools/wptrunner/wptrunner/executors/platformaccessibility/ia2/ia2_api_all.tlb differ
diff --git a/tools/wptrunner/wptrunner/testdriver-extra.js b/tools/wptrunner/wptrunner/testdriver-extra.js
index 6f6b13620782f5..51f9d1ababfd48 100644
--- a/tools/wptrunner/wptrunner/testdriver-extra.js
+++ b/tools/wptrunner/wptrunner/testdriver-extra.js
@@ -671,8 +671,7 @@
     window.test_driver_internal.set_global_privacy_control = function(gpc, context=null) {
         return create_action("set_global_privacy_control", {gpc});
     };
-  
-  
+
     window.test_driver_internal.bidi.speculation.prefetch_status_updated.subscribe =
         function(params) {
         return subscribe(
@@ -688,5 +687,9 @@
             'speculation.prefetchStatusUpdated', on_event);
         return () => event_target.removeEventListener(
                     'speculation.prefetchStatusUpdated', on_event);
-    }; 
+    };
+
+    window.test_driver_internal.test_accessibility_api = function(dom_id, test, api, url) {
+        return create_action("test_accessibility_api", {dom_id, test, api, url});
+    };
 })();
diff --git a/tools/wptrunner/wptrunner/testrunner.py b/tools/wptrunner/wptrunner/testrunner.py
index cc81b73511324e..eceee2f219c68e 100644
--- a/tools/wptrunner/wptrunner/testrunner.py
+++ b/tools/wptrunner/wptrunner/testrunner.py
@@ -343,7 +343,8 @@ def __init__(self, suite_name, index, test_queue,
                  pause_after_test=False, pause_on_unexpected=False,
                  restart_on_unexpected=True, debug_info=None,
                  capture_stdio=True, restart_on_new_group=True, recording=None,
-                 max_restarts=5, max_restart_backoff=0, update_status_on_crash=True):
+                 max_restarts=5, max_restart_backoff=0, update_status_on_crash=True,
+                 product_name=None):
         """Thread that owns a single TestRunner process and any processes required
         by the TestRunner (e.g. the Firefox binary).
 
@@ -363,6 +364,7 @@ def __init__(self, suite_name, index, test_queue,
         self.manager_number = index
         self.test_implementation_key = None
         self.test_implementations = test_implementations
+        self.product_name = product_name
 
         # Flags used to shut down this thread if we get a sigint
         self.parent_stop_flag = stop_flag
@@ -648,6 +650,7 @@ def get_executor_implementation(self, impl):
         executor_kwargs["group_metadata"] = self.state.group_metadata
         executor_kwargs["browser_settings"] = self.browser.browser_settings
         executor_browser_cls, executor_browser_kwargs = self.browser.browser.executor_browser()
+        executor_browser_kwargs["product_name"] = self.product_name
         return ExecutorImplementation(impl.executor_cls,
                                       executor_kwargs,
                                       executor_browser_cls,
@@ -1049,8 +1052,10 @@ def __init__(self, suite_name, test_queue_builder, test_implementations,
                  recording=None,
                  max_restarts=5,
                  max_restart_backoff=0,
-                 update_status_on_crash=False):
+                 update_status_on_crash=False,
+                 product_name=None):
         self.suite_name = suite_name
+        self.product_name = product_name
         self.test_queue_builder = test_queue_builder
         self.test_implementations = test_implementations
         self.pause_after_test = pause_after_test
@@ -1100,7 +1105,8 @@ def run(self, tests):
                                         recording=self.recording,
                                         max_restarts=self.max_restarts,
                                         max_restart_backoff=self.max_restart_backoff,
-                                        update_status_on_crash=self.update_status_on_crash)
+                                        update_status_on_crash=self.update_status_on_crash,
+                                        product_name=self.product_name)
             manager.start()
             self.pool.add(manager)
         self.wait()
diff --git a/tools/wptrunner/wptrunner/wptcommandline.py b/tools/wptrunner/wptrunner/wptcommandline.py
index 994f2520000ebe..daf0980b799356 100644
--- a/tools/wptrunner/wptrunner/wptcommandline.py
+++ b/tools/wptrunner/wptrunner/wptcommandline.py
@@ -161,6 +161,9 @@ def create_parser(product_choices=None):
                                       action="append",
                                       choices=["not-implementing", "backlog", "implementing"],
                                       help="Skip tests that have the given implementation status")
+    test_selection_group.add_argument("--enable-accessibility-api",
+                                      action="store_true",
+                                      help="Enable test infrastructure and browser configurations for accessibility API tests")
     # TODO(bashi): Remove this when WebTransport over HTTP/3 server is enabled by default.
     test_selection_group.add_argument("--enable-webtransport-h3",
                                       action="store_true",
diff --git a/tools/wptrunner/wptrunner/wptrunner.py b/tools/wptrunner/wptrunner/wptrunner.py
index c7d8938f25d1e0..819a38a93b9b5b 100644
--- a/tools/wptrunner/wptrunner/wptrunner.py
+++ b/tools/wptrunner/wptrunner/wptrunner.py
@@ -333,7 +333,8 @@ def run_test_iteration(test_status, test_loader, test_queue_builder,
                           recording=recording,
                           max_restarts=kwargs["max_restarts"],
                           max_restart_backoff=kwargs["max_restart_backoff"],
-                          update_status_on_crash=kwargs["update_status_on_crash"]
+                          update_status_on_crash=kwargs["update_status_on_crash"],
+                          product_name=product.name
                           ) as manager_group:
             try:
                 handle_interrupt_signals()
