diff --git a/doc/requirements.txt b/doc/requirements.txt
index 399823e26a..ba9d95a4aa 100644
--- a/doc/requirements.txt
+++ b/doc/requirements.txt
@@ -5,7 +5,6 @@ openstackdocstheme>=2.2.1 # Apache-2.0
 reno>=3.1.0 # Apache-2.0
 doc8>=0.6.0 # Apache-2.0
 sphinx>=2.0.0,!=2.1.0 # BSD
-mock>=2.0.0 # BSD
 os-api-ref>=1.4.0 # Apache-2.0
 ddt>=1.0.1 # MIT
 fixtures>=3.0.0 # Apache-2.0/BSD