diff --git a/setup.py b/setup.py
index 5c8c584..24c3b97 100644
--- a/setup.py
+++ b/setup.py
@@ -54,7 +54,7 @@
         )
 
 test_requirements = [
-    "pytest>=3.6.0",
+    "pytest>=3.6.0,!=3.9.0,!=3.9.1",
     "pretend",
     "iso8601",
     "pytz",