diff --git a/requirements_dev.txt b/requirements_dev.txt
index d113083..2433d0b 100644
--- a/requirements_dev.txt
+++ b/requirements_dev.txt
@@ -3,6 +3,7 @@ bumpversion==0.5.3
 wheel==0.32.2
 watchdog==0.9.0
 flake8==3.6.0
+coverage==4.5.3
 tox==3.8.6
 coverage==4.5.1
 Sphinx==2.0.1