diff --git a/requirements-dev.txt b/requirements-dev.txt
index 73b807835..e06cad45c 100644
--- a/requirements-dev.txt
+++ b/requirements-dev.txt
@@ -1,4 +1,5 @@
 coverage==3.7.1
+flake8==3.5.0
 mock>=1.0.1
 pytest==2.7.2
 pytest-cov==2.1.0