diff --git a/.github/workflows/tox.yaml b/.github/workflows/tox.yaml
index ddfeff1e0..16fffe08a 100644
--- a/.github/workflows/tox.yaml
+++ b/.github/workflows/tox.yaml
@@ -20,7 +20,7 @@ jobs:
     - name: Install dependencies
       run: |
         python -m pip install --upgrade pip
-        pip install tox tox-gh-actions
+        pip install "tox<4.0" tox-gh-actions
     - name: Lint with tox
       run: tox -e pep8
     - name: Test with tox
diff --git a/setup.py b/setup.py
index 8fe59bfae..5f4f4f963 100644
--- a/setup.py
+++ b/setup.py
@@ -69,7 +69,7 @@
 ]
 
 tests_require = [
-    'tox >= 2.3.1',
+    'tox',
 ]
 
 
diff --git a/tox.ini b/tox.ini
index 73510daa6..68e149122 100644
--- a/tox.ini
+++ b/tox.ini
@@ -22,6 +22,9 @@ minversion = 3.2.0
 [testenv]
 setenv = VIRTUAL_ENV={envdir}
          PYTHONHASHSEED=0
+allowlist_externals =
+    {toxinidir}/pip.sh
+
 install_command =
   {toxinidir}/pip.sh install {opts} {packages}