diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index ee2e7f2..abd7fc2 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -63,7 +63,7 @@ jobs:
         run: |
           set -x
           python -VV
-          python -m pip install tox
+          python -m pip install 'tox<4'
           python -m tox --version
       - name: Test ${{ matrix.tox.name }}
         run: |