diff --git a/.github/envs/environment-3.13.yml b/.github/envs/environment-3.14.yml
similarity index 93%
rename from .github/envs/environment-3.13.yml
rename to .github/envs/environment-3.14.yml
index f2fb8b39..adc1f393 100644
--- a/.github/envs/environment-3.13.yml
+++ b/.github/envs/environment-3.14.yml
@@ -3,7 +3,7 @@ channels:
   - conda-forge
 dependencies:
   # required dependencies
-  - python=3.13
+  - python=3.14
   - dask >=2025.3.1,<2025.4.0
   - aiohttp
   - requests
diff --git a/.github/workflows/awkward-main.yml b/.github/workflows/awkward-main.yml
index 321f98a2..eb8e891c 100644
--- a/.github/workflows/awkward-main.yml
+++ b/.github/workflows/awkward-main.yml
@@ -32,7 +32,7 @@ jobs:
     - name: Setup Python
       uses: actions/setup-python@v7
       with:
-        python-version: "3.13"
+        python-version: "3.14"
     - name: Prepare awkward-cpp
       run: |
         python3 -m pip install nox
diff --git a/.github/workflows/conda-tests.yml b/.github/workflows/conda-tests.yml
index b0dfe392..74860881 100644
--- a/.github/workflows/conda-tests.yml
+++ b/.github/workflows/conda-tests.yml
@@ -17,7 +17,7 @@ jobs:
     strategy:
       matrix:
         platform: [ubuntu-latest, macos-latest, windows-latest]
-        python-version: ["3.13"]
+        python-version: ["3.14"]
     runs-on: ${{matrix.platform}}
     steps:
     - name: Checkout source
diff --git a/.github/workflows/coverage.yml b/.github/workflows/coverage.yml
index eeee49b3..30856501 100644
--- a/.github/workflows/coverage.yml
+++ b/.github/workflows/coverage.yml
@@ -24,7 +24,7 @@ jobs:
     - name: Setup Python
       uses: actions/setup-python@v7
       with:
-        python-version: "3.13"
+        python-version: "3.14"
     - name: Generate Report
       run: |
         pip install wheel
diff --git a/.github/workflows/pypi-tests.yml b/.github/workflows/pypi-tests.yml
index 66cf2fd5..829fc86e 100644
--- a/.github/workflows/pypi-tests.yml
+++ b/.github/workflows/pypi-tests.yml
@@ -18,7 +18,7 @@ jobs:
       fail-fast: false
       matrix:
         platform: [ubuntu-latest, macos-latest, windows-latest]
-        python-version: ["3.10", "3.11", "3.12", "3.13", "3.14", "3.14t"]
+        python-version: ["3.10", "3.11", "3.12", "3.13", "3.14", "3.14t", "3.15", "3.15t"]
     runs-on: ${{matrix.platform}}
     steps:
     - name: Checkout
diff --git a/.github/workflows/uproot-main.yml b/.github/workflows/uproot-main.yml
index 86d64f70..5def0446 100644
--- a/.github/workflows/uproot-main.yml
+++ b/.github/workflows/uproot-main.yml
@@ -24,7 +24,7 @@ jobs:
     - name: Setup Python
       uses: actions/setup-python@v7
       with:
-        python-version: "3.13"
+        python-version: "3.14"
     - name: Install and test
       run: |
         python3 -m pip install pip wheel -U
diff --git a/pyproject.toml b/pyproject.toml
index 31f285f3..9f28f669 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -29,6 +29,7 @@ classifiers = [
   "Programming Language :: Python :: 3.12",
   "Programming Language :: Python :: 3.13",
   "Programming Language :: Python :: 3.14",
+  "Programming Language :: Python :: 3.15",
   "Topic :: Scientific/Engineering",
   "Topic :: Scientific/Engineering :: Information Analysis",
   "Topic :: Scientific/Engineering :: Mathematics",