diff --git a/.github/workflows/release.yml b/.github/workflows/release.yml
index 369ebc8e..1e455693 100644
--- a/.github/workflows/release.yml
+++ b/.github/workflows/release.yml
@@ -19,10 +19,10 @@ jobs:
       contents: write
 
     steps:
-      - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
+      - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
 
       - name: Set up Python
-        uses: actions/setup-python@a309ff8b426b58ec0e2a45f0f869d46889d02405 # v6
+        uses: actions/setup-python@6d4fd22b20465ccc0f7354476588e8df7c9ca0e0 # v7.1.0
         with:
           python-version: "3.x"
 
diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index e8e7fa81..7a3c535a 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -26,28 +26,38 @@ jobs:
         os:
           - ubuntu-latest
         python-version:
-          ["3.10", "3.11", "3.12", "3.13", "3.14", "3.14t", pypy3.11]
+          ["3.10", "3.11", "3.12", "3.13", "3.14", "3.15", "3.15t", pypy3.11]
         include:
           # Windows: Test lowest and highest supported Python versions
           - os: windows-latest
             python-version: "3.10"
           - os: windows-latest
-            python-version: "3.14"
+            python-version: "3.15"
+
+    env:
+      # Select the tox envs for this matrix entry (see `[gh]` in `tox.ini`).
+      TOX_GH_MAJOR_MINOR: ${{ matrix.python-version }}
+      # Use uv-managed interpreters everywhere.
+      UV_PYTHON_PREFERENCE: only-managed
 
     steps:
-      - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
+      - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
 
-      - name: Set up Python ${{ matrix.python-version }}
-        uses: actions/setup-python@a309ff8b426b58ec0e2a45f0f869d46889d02405 # v6
+      - name: Install uv
+        uses: astral-sh/setup-uv@07a047e608db84b3d8c06cd9a7c7dcc9c355c18e # v10.3.2
         with:
-          python-version: ${{ matrix.python-version }}
-          allow-prereleases: true
+          version-file: requirements-ci.txt
+          enable-cache: true
+          cache-dependency-glob: |
+            pyproject.toml
+            tox.ini
+            requirements-ci.txt
 
-      - name: Upgrade pip
-        run: python -m pip install --upgrade pip
+      - name: Install tox
+        run: uv tool install --python 3.15 --with-requirements requirements-ci.txt tox
 
-      - name: Install dependencies
-        run: pip install tox tox-gh-actions
+      - name: Setup test suite
+        run: tox run -v --notest --skip-missing-interpreters false
 
-      - name: Test with tox
-        run: tox
+      - name: Run test suite
+        run: tox run --skip-pkg-install
diff --git a/CHANGELOG.md b/CHANGELOG.md
index e5f25414..71c9740d 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -7,6 +7,10 @@ project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
 ## [Unreleased]
 
+### Added
+
+- Add support for Python 3.15.
+
 ### Fixed
 
 - Fix a package build deprecation warning caused by a non-string `license` value in `pyproject.toml` by [@kurtmckee] in [#648]
diff --git a/MANIFEST.in b/MANIFEST.in
index bf0d47e6..afa35896 100644
--- a/MANIFEST.in
+++ b/MANIFEST.in
@@ -9,5 +9,6 @@ include .coveragerc
 include .editorconfig
 include Makefile
 include requirements.txt
+include requirements-ci.txt
 include requirements-docs.txt
 include src/dotenv/py.typed
diff --git a/pyproject.toml b/pyproject.toml
index 1619e9d4..7dc2a711 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -27,6 +27,7 @@ classifiers = [
     "Programming Language :: Python :: 3.12",
     "Programming Language :: Python :: 3.13",
     "Programming Language :: Python :: 3.14",
+    "Programming Language :: Python :: 3.15",
     "Programming Language :: Python :: Implementation :: PyPy",
     "Intended Audience :: Developers",
     "Intended Audience :: System Administrators",
diff --git a/requirements-ci.txt b/requirements-ci.txt
new file mode 100644
index 00000000..002cc7aa
--- /dev/null
+++ b/requirements-ci.txt
@@ -0,0 +1,5 @@
+# Tooling installed by `.github/workflows/test.yml`.
+tox==4.67.4
+tox-gh==1.9.1
+tox-uv==1.37.2
+uv==0.13.6
diff --git a/tox.ini b/tox.ini
index 6d1f25f8..1f49dc26 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,26 +1,30 @@
 [tox]
-envlist = lint,py{310,311,312,313,314,314t},pypy3,manifest,coverage-report
+envlist = lint,py{310,311,312,313,314,315,315t},pypy3,manifest,coverage-report
 
-[gh-actions]
+[gh]
 python =
-    3.10: py310
-    3.11: py311
-    3.12: py312
-    3.13: py313, lint, manifest
-    3.14: py314
-    3.14t: py314t
-    pypy-3.11: pypy3
+    3.10 = py310
+    3.11 = py311
+    3.12 = py312
+    3.13 = py313, lint, manifest
+    3.14 = py314
+    3.15 = py315
+    3.15t = py315t
+    pypy3.11 = pypy3
 
 [testenv]
 deps =
     pytest
     pytest-cov
     click
-    py{310,311,312,313,314,314t,pypy3}: ipython
+    py{310,311,312,313,314,315,315t},pypy3: ipython
 commands = pytest --cov --cov-report=term-missing {posargs}
 depends =
-    py{310,311,312,313,314,314t},pypy3: coverage-clean
-    coverage-report: py{310,311,312,313,314,314t},pypy3
+    py{310,311,312,313,314,315,315t},pypy3: coverage-clean
+    coverage-report: py{310,311,312,313,314,315,315t},pypy3
+
+[testenv:pypy3]
+base_python = pypy3.11
 
 [testenv:lint]
 skip_install = true
@@ -30,6 +34,7 @@ deps =
 commands =
     ruff check src tests
     ruff format --check src tests
+    mypy --python-version=3.15 src tests
     mypy --python-version=3.14 src tests
     mypy --python-version=3.13 src tests
     mypy --python-version=3.12 src tests