diff --git a/.github/workflows/publish.yaml b/.github/workflows/publish.yaml
index f6b765af..b6605448 100644
--- a/.github/workflows/publish.yaml
+++ b/.github/workflows/publish.yaml
@@ -59,6 +59,7 @@ jobs:
           CIBW_ARCHS_LINUX: auto aarch64
           CIBW_ARCHS_MACOS: auto universal2
           CIBW_BUILD_FRONTEND: build
+          CIBW_FREE_THREADED_SUPPORT: 1
       - uses: actions/upload-artifact@834a144ee995460fba8ed112a2fc961b36a5ec5a # v4.3.6
         with:
           name: build-wheels-${{ matrix.os }}
diff --git a/.github/workflows/tests.yaml b/.github/workflows/tests.yaml
index 4a755422..d8b0c556 100644
--- a/.github/workflows/tests.yaml
+++ b/.github/workflows/tests.yaml
@@ -22,6 +22,7 @@ jobs:
       matrix:
         include:
           - {python: '3.13'}
+          - {name: 'Free-threaded', python: '3.13', free-threaded: true}
           - {python: '3.12'}
           - {name: Windows, python: '3.12', os: windows-latest}
           - {name: Mac, python: '3.12', os: macos-latest}
@@ -33,13 +34,21 @@ jobs:
     steps:
       - uses: actions/checkout@692973e3d937129bcbf40652eb9f2f61becf3332 # v4.1.7
       - uses: actions/setup-python@39cd14951b08e74b54015e9e001cdefcf80e669f # v5.1.1
+        if: ${{ !matrix.free-threaded }}
         with:
           python-version: ${{ matrix.python }}
           allow-prereleases: true
           cache: pip
           cache-dependency-path: requirements*/*.txt
+      - uses: deadsnakes/action@e640ac8743173a67cca4d7d77cd837e514bf98e8 # v3.2.0
+        if: ${{ matrix.free-threaded }}
+        with:
+          python-version: ${{ matrix.python }}
+          nogil: true
       - run: pip install tox
-      - run: tox run -e ${{ matrix.tox || format('py{0}', matrix.python) }}
+      - env:
+          PYTHON_GIL: ${{ matrix.free-threaded && '0' || '1' }}
+        run: tox run -e ${{ matrix.tox || format('py{0}', matrix.python) }}
   typing:
     runs-on: ubuntu-latest
     steps:
diff --git a/tox.ini b/tox.ini
index 1daab3da..ba3c4148 100644
--- a/tox.ini
+++ b/tox.ini
@@ -9,6 +9,7 @@ skip_missing_interpreters = true
 
 [testenv]
 package = wheel
+pass_env = PYTHON_GIL
 constrain_package_deps = true
 use_frozen_constraints = true
 deps = -r requirements/tests.txt