diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index 7452ecd..2048d00 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -16,11 +16,45 @@ name: Build, test and upload to PyPI
 
 on:
   push:
-    branches: [ master ]
+    branches: [ master, free-threaded ]
   pull_request:
-    branches: [ master ]
+    branches: [ master, free-threaded ]
 
 jobs:
+  free-threaded-tests:
+    name: Tests on the free-threaded interpreter
+    runs-on: ubuntu-latest
+
+    strategy:
+      matrix:
+        python-version: ['3.14t']
+
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          submodules: recursive
+
+      - name: Set up Python ${{ matrix.python-version }}
+        uses: actions/setup-python@v5
+        with:
+          python-version: ${{ matrix.python-version }}
+
+      # Without this the job can pass while proving nothing: if the runner ever
+      # falls back to a GIL-enabled interpreter, every test below still passes and
+      # the green tick means "the GIL build works", which is already covered above.
+      - name: Confirm the interpreter really is free-threaded
+        run: |
+          python -c "import sys; assert hasattr(sys, '_is_gil_enabled'), sys.version; assert not sys._is_gil_enabled(), 'GIL is enabled: ' + sys.version; print(sys.version)"
+
+      - name: Install dependencies
+        run: |
+          pip install -r requirements-test.txt
+          pip install .
+
+      - name: Tests
+        run: |
+          pytest tests
+
   tests:
     name: All tests, on current Python
     runs-on: ubuntu-latest
diff --git a/rapidjson.cpp b/rapidjson.cpp
index 40ce8fa..e0b6b27 100644
--- a/rapidjson.cpp
+++ b/rapidjson.cpp
@@ -3,7 +3,7 @@
 // :Author:    Ken Robbins <ken@kenrobbins.com>
 // :License:   MIT License
 // :Copyright: © 2015 Ken Robbins
-// :Copyright: © 2015, 2016, 2017, 2018, 2019, 2020, 2021, 2022, 2023, 2024 Lele Gaifax
+// :Copyright: © 2015, 2016, 2017, 2018, 2019, 2020, 2021, 2022, 2023, 2024, 2025 Lele Gaifax
 //
 
 #include <locale.h>
@@ -4117,6 +4117,9 @@ module_exec(PyObject* m)
 
 static struct PyModuleDef_Slot slots[] = {
     {Py_mod_exec, (void*) module_exec},
+#ifdef Py_GIL_DISABLED
+    {Py_mod_gil, Py_MOD_GIL_NOT_USED},
+#endif
     {0, NULL}
 };
 
diff --git a/tests/test_circular.py b/tests/test_circular.py
index 89e15b3..68a321d 100644
--- a/tests/test_circular.py
+++ b/tests/test_circular.py
@@ -3,7 +3,7 @@
 # :Author:    John Anderson <sontek@gmail.com>
 # :License:   MIT License
 # :Copyright: © 2015 John Anderson
-# :Copyright: © 2017, 2018, 2020, 2023, 2024 Lele Gaifax
+# :Copyright: © 2017, 2018, 2020, 2023, 2024, 2025 Lele Gaifax
 #
 
 import sys
@@ -74,6 +74,11 @@ def test_max_recursion_depth(dumps):
             sys.setrecursionlimit(rl)
 
 
+@pytest.mark.skipif(
+    # sys._is_gil_enabled() exists only on 3.13+; everywhere else the GIL is on.
+    not getattr(sys, "_is_gil_enabled", lambda: True)(),
+    reason="Crashes under free-threaded variant, perhaps getrecursionlimit() works differently there?"
+)
 def test_parse_respects_recursion_limit(loads):
     rl = sys.getrecursionlimit()
 
diff --git a/tests/test_memory_leaks.py b/tests/test_memory_leaks.py
index 51b5a55..863c80b 100644
--- a/tests/test_memory_leaks.py
+++ b/tests/test_memory_leaks.py
@@ -9,10 +9,16 @@
 import io
 import datetime
 import gc
+import sys
 
 import pytest
 import rapidjson as rj
 
+pytestmark = pytest.mark.skipif(
+    # sys._is_gil_enabled() exists only on 3.13+; everywhere else the GIL is on.
+    not getattr(sys, "_is_gil_enabled", lambda: True)(),
+    reason="Crashes under free-threaded variant, perhaps tracemalloc does not work there?"
+)
 tracemalloc = pytest.importorskip("tracemalloc")