diff --git a/.ci/install.sh b/.ci/install.sh
index 1eb098be9c1..8e65f64c447 100755
--- a/.ci/install.sh
+++ b/.ci/install.sh
@@ -37,12 +37,18 @@ python3 -m pip install -U pytest-timeout
 python3 -m pip install pyroma
 
 if [[ $(uname) != CYGWIN* ]]; then
-    python3 -m pip install numpy
+    # TODO Update condition when NumPy supports free-threading
+    if [[ "$PYTHON_GIL" == "0" ]]; then
+        python3 -m pip install numpy --index-url https://pypi.anaconda.org/scientific-python-nightly-wheels/simple
+    else
+        python3 -m pip install numpy
+    fi
 
     # PyQt6 doesn't support PyPy3
     if [[ $GHA_PYTHON_VERSION == 3.* ]]; then
         sudo apt-get -qq install libegl1 libxcb-cursor0 libxcb-icccm4 libxcb-image0 libxcb-keysyms1 libxcb-randr0 libxcb-render-util0 libxcb-shape0 libxkbcommon-x11-0
-        python3 -m pip install pyqt6
+        # TODO Update condition when pyqt6 supports free-threading
+        if ! [[ "$PYTHON_GIL" == "0" ]]; then python3 -m pip install pyqt6 ; fi
     fi
 
     # Pyroma uses non-isolated build and fails with old setuptools
diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 0972459b0fb..6e63333b0da 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -50,26 +50,24 @@ jobs:
           "3.9",
         ]
         include:
-        - python-version: "3.11"
-          PYTHONOPTIMIZE: 1
-          REVERSE: "--reverse"
-        - python-version: "3.10"
-          PYTHONOPTIMIZE: 2
+        - { python-version: "3.11", PYTHONOPTIMIZE: 1, REVERSE: "--reverse" }
+        - { python-version: "3.10", PYTHONOPTIMIZE: 2 }
+        # Free-threaded
+        - { os: "ubuntu-latest", python-version: "3.13-dev", disable-gil: true }
         # M1 only available for 3.10+
-        - os: "macos-13"
-          python-version: "3.9"
+        - { os: "macos-13", python-version: "3.9" }
         exclude:
-        - os: "macos-14"
-          python-version: "3.9"
+        - { os: "macos-14", python-version: "3.9" }
 
     runs-on: ${{ matrix.os }}
-    name: ${{ matrix.os }} Python ${{ matrix.python-version }}
+    name: ${{ matrix.os }} Python ${{ matrix.python-version }} ${{ matrix.disable-gil && 'free-threaded' || '' }}
 
     steps:
     - uses: actions/checkout@v4
 
     - name: Set up Python ${{ matrix.python-version }}
       uses: actions/setup-python@v5
+      if: "${{ !matrix.disable-gil }}"
       with:
         python-version: ${{ matrix.python-version }}
         allow-prereleases: true
@@ -78,6 +76,18 @@ jobs:
           ".ci/*.sh"
           "pyproject.toml"
 
+    - name: Set up Python ${{ matrix.python-version }} (free-threaded)
+      uses: deadsnakes/action@v3.1.0
+      if: "${{ matrix.disable-gil }}"
+      with:
+        python-version: ${{ matrix.python-version }}
+        nogil: ${{ matrix.disable-gil }}
+
+    - name: Set PYTHON_GIL
+      if: "${{ matrix.disable-gil }}"
+      run: |
+        echo "PYTHON_GIL=0" >> $GITHUB_ENV
+
     - name: Build system information
       run: python3 .github/workflows/system-info.py