diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index c31f076c..6b6b5204 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -65,7 +65,7 @@ jobs:
           sudo apt-get -qq -y install "libpq-dev=${pqver}" "libpq5=${pqver}"
 
       - name: Install tox
-        run: pip install tox
+        run: pip install "tox < 4"
       - uses: actions/setup-python@v4
         with:
           python-version: ${{ matrix.python }}