diff --git a/tests/requirements.txt b/tests/requirements.txt
index 446044f..ecf0064 100644
--- a/tests/requirements.txt
+++ b/tests/requirements.txt
@@ -1,5 +1,5 @@
 flake8==3.5.0
-tox==3.4.0
+tox==3.12.0
 coverage==4.5.1
 cryptography==2.3.1
 PyYAML==3.13