diff --git a/requirements_dev.txt b/requirements_dev.txt
index cf9af67..5eef72e 100644
--- a/requirements_dev.txt
+++ b/requirements_dev.txt
@@ -1,6 +1,6 @@
 wheel==0.32.1
 flake8==3.5.0
-tox==3.4.0
+tox==3.5.3
 coverage==4.5.1
 coveralls==1.5.1
 pytest==3.8.2