diff --git a/requirements_dev.txt b/requirements_dev.txt
index deed99b..707ae4a 100644
--- a/requirements_dev.txt
+++ b/requirements_dev.txt
@@ -1,6 +1,6 @@
 codecov==2.0.15
 httpretty==0.8.10
-mock==2.0.0
+mock==5.1.0
 moto==1.2.0
 pytest-cov==2.5.1
 pytest==3.4.2