diff --git a/requirements_test.txt b/requirements_test.txt
index 40311da..66fe885 100644
--- a/requirements_test.txt
+++ b/requirements_test.txt
@@ -5,7 +5,7 @@ jinja2==2.9.6
 pip==9.0.1
 wheel==0.30.0
 flake8==3.4.1
-tox==2.9.1
+tox==3.9.0
 coverage==4.4.1
 pytest==3.2.3
 pytest-cov==2.5.1