diff --git a/requirements_dev.txt b/requirements_dev.txt
index 3292490..0ec1e99 100644
--- a/requirements_dev.txt
+++ b/requirements_dev.txt
@@ -6,7 +6,7 @@ watchdog==0.9.0
 coverage==4.5.3
 sphinxcontrib-napoleon==0.7
 pytest==4.3.0
-tox==3.7.0
+tox==3.8.4
 flake8==3.7.6
 pyflakes==2.1.1
 pyyaml>=4.2b1