diff --git a/doc/requirements.txt b/doc/requirements.txt
index 31f41ec8223..ab289e81c60 100644
--- a/doc/requirements.txt
+++ b/doc/requirements.txt
@@ -6,6 +6,7 @@ sphinx_feature_classification>=1.0.0 # Apache-2.0
 openstackdocstheme>=2.2.1 # Apache-2.0
 oslotest>=3.2.0 # Apache-2.0
 reno>=3.1.0 # Apache-2.0
+WebTest>=2.0.27 # MIT
 # NOTE(ralonsoh): pyroute2 module should be installed and the version limited
 # according to upper-constraints.txt
 pyroute2>=0.6.4;sys_platform!='win32' # Apache-2.0 (+ dual licensed GPL2)