diff --git a/test/firefox_user.js b/test/firefox_user.js
index dccb6e556bfc0..d3860bb478af7 100644
--- a/test/firefox_user.js
+++ b/test/firefox_user.js
@@ -91,3 +91,5 @@ user_pref("gfx.offscreencanvas.enabled", true);
 user_pref("javascript.options.wasm_memory64", true);
 // Do not ask user consent to enable audio playback (0: Allow autoplay for all media)
 user_pref("media.autoplay.default", 0);
+// Enable JSPI support
+user_pref("javascript.options.wasm_js_promise_integration", true);
diff --git a/test/test_browser.py b/test/test_browser.py
index a28805e0bedd8..4725684c01055 100644
--- a/test/test_browser.py
+++ b/test/test_browser.py
@@ -274,8 +274,8 @@ def setUpClass(cls):
       print()
 
   def require_jspi(self):
-    if not is_chrome():
-      self.skipTest(f'Current browser ({get_browser()}) does not support JSPI. Only chromium-based browsers ({CHROMIUM_BASED_BROWSERS}) support JSPI today.')
+    if not is_chrome() and not is_firefox():
+      self.skipTest(f'Current browser ({get_browser()}) does not support JSPI. Only chromium-based browsers ({CHROMIUM_BASED_BROWSERS}) and firefox support JSPI today.')
     super().require_jspi()
 
   def post_manual_reftest(self):
@@ -5332,7 +5332,7 @@ def test_wasmfs_fetch_backend_threaded(self, args):
   })
   @no_safari('TODO: Fails with abort:Assertion failed: err == 0') # Fails in Safari 17.6 (17618.3.11.11.7, 17618), Safari 26.0.1 (21622.1.22.11.15)
   def test_wasmfs_opfs(self, args):
-    if '-sJSPI' in args:
+    if is_jspi(args):
       self.require_jspi()
     test = test_file('wasmfs/wasmfs_opfs.c')
     args = ['-sWASMFS', '-O3'] + args