diff --git a/lower-constraints.txt b/lower-constraints.txt
index 53239d36..435952ae 100644
--- a/lower-constraints.txt
+++ b/lower-constraints.txt
@@ -45,7 +45,6 @@ linecache2==1.0.0
 Mako==1.0.7
 MarkupSafe==1.0
 mccabe==0.2.1
-mock==2.0.0
 monotonic==1.4
 mox3==0.25.0
 msgpack==0.5.6