diff --git a/requirements.txt b/requirements.txt
index 9329fe72..6be0d2ca 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -12,6 +12,7 @@ oslo.utils>=1.6.0 # Apache-2.0
 iso8601>=0.1.9
 oslo.log>=1.2.0 # Apache-2.0
 oslo.i18n>=1.5.0 # Apache-2.0
-mock>=1.0
+mock>=1.1;python_version!='2.6'
+mock==1.0.1;python_version=='2.6'
 fixtures>=1.3.1
 WebOb>=1.2.3