diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index efd40b4bd..97b4b4a35 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -46,7 +46,7 @@ jobs:
         - name: Install tox
           run: |
             python -m pip install --upgrade pip
-            pip install tox
+            pip install "tox<4"
         - name: Tox test
           env:
             TOXENV: ${{ matrix.tox_env }}
@@ -82,7 +82,7 @@ jobs:
         - name: Install tox
           run: |
             python -m pip install --upgrade pip
-            pip install tox
+            pip install "tox<4"
         - name: Tox test
           env:
             TOXENV: postgres
diff --git a/tools/dev-requirements.txt b/tools/dev-requirements.txt
index 962b6480a..8a2a518b3 100644
--- a/tools/dev-requirements.txt
+++ b/tools/dev-requirements.txt
@@ -1,3 +1,3 @@
 packaging
-tox
+tox<4
 -e .[dev]