diff --git a/tox.ini b/tox.ini
index eca63a758a5f6a20b1cd11887330817fec7908d7..cbe278cd8f7b1f3cd38760cb63a1b009786edcd2 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,7 +1,7 @@
 [tox]
 skipsdist = True
 skip_missing_interpreters = true
-envlist = py37,py38
+envlist = py37,py38,py39
 
 [testenv]
 whitelist_externals = poetry
@@ -22,8 +22,8 @@ setenv =
 
 [testenv:lint]
 commands =
-    - poetry run black --check --diff aleksis/
-    - poetry run isort -c --diff --stdout aleksis/
+    poetry run black --check --diff aleksis/
+    poetry run isort -c --diff --stdout aleksis/
     poetry run flake8 {posargs} aleksis/
 
 [testenv:security]