diff --git a/lower-constraints.txt b/lower-constraints.txt
index cee625d..ad7996f 100644
--- a/lower-constraints.txt
+++ b/lower-constraints.txt
@@ -18,7 +18,6 @@
 iso8601==0.1.11
 keystoneauth1==3.4.0
 linecache2==1.0.0
-mock==2.0.0
 monotonic==0.6
 mox3==0.20.0
 msgpack-python==0.4.0