diff --git a/tox.ini b/tox.ini
index 9077838a320efa1d0dff82c1a7d61afbf1094cc4..94cb7805f2ea0750eef10aac3f24c83434d2817f 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,5 +1,5 @@
 [tox]
-envlist = {py35,py36,py37,py38},lint,doc
+envlist = {py35,py36,py37,py38,py39},lint,doc
 
 [testenv]
 whitelist_externals =
@@ -12,6 +12,7 @@ basepython =
   py36: python3.6
   py37: python3.7
   py38: python3.8
+  py39: python3.9
 
 deps =
   .[test]