diff --git a/pyproject.toml b/pyproject.toml
index e963cfa..88ef426 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -25,6 +25,7 @@ classifiers = [
   "Programming Language :: Python :: 3.6",
   "Programming Language :: Python :: 3.7",
   "Programming Language :: Python :: 3.8",
+  "Programming Language :: Python :: 3.9",
   "Programming Language :: Python :: Implementation :: CPython",
 ]
 
diff --git a/tox.ini b/tox.ini
index e2bcc85..bf4ce7c 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,6 +1,7 @@
 [tox]
-envlist = py36, py37, py38, static, static-tests, security
+envlist = py36, py37, py38, py39, static, static-tests, security
 isolated_build = true
+skip_missing_interpreters = true
 
 [testenv]
 description = Run the tests