diff --git a/tox.ini b/tox.ini
index 3ffa1342..61c3e75d 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,6 +1,6 @@
 [tox]
 envlist =
-  py37-{pytest,lint,invalidcode}
+  py{37,39}-{pytest,lint,invalidcode}
   format
   format-check
   docs
@@ -11,13 +11,13 @@ usedevelop = True
 passenv = *
 extras = tests
 deps =
-  py37-pytest: .[tests]
-  py37-lint: flake8
-  py37-invalidcode: flake8
+  py{37,39}-pytest: .[tests]
+  py{37,39}-lint: flake8
+  py{37,39}-invalidcode: flake8
 commands =
-    py37-pytest: pytest {posargs} -c pytest.ini
-    py37-lint: flake8 moulinette test
-    py37-invalidcode: flake8 moulinette test --select F
+    py{37,39}-pytest: pytest {posargs} -c pytest.ini
+    py{37,39}-lint: flake8 moulinette test
+    py{37,39}-invalidcode: flake8 moulinette test --select F
 
 [gh-actions]
 python =