diff --git a/tox.ini b/tox.ini
index b006339f2..ace40708b 100644
--- a/tox.ini
+++ b/tox.ini
@@ -5,7 +5,7 @@ envlist = py3{6,7}-cov, htmlcov
 [testenv]
 deps =
     cov: coverage>=4.3
-    pytest
+    pytest==5.1.1
     pytest-randomly
     -rrequirements.txt
 extras =