diff --git a/doc/requirements.txt b/doc/requirements.txt
index 1ade022..467e820 100644
--- a/doc/requirements.txt
+++ b/doc/requirements.txt
@@ -2,6 +2,7 @@
 # of appearance. Changing the order has an impact on the overall integration
 # process, which may cause wedges in the gate later.
 
+sphinxcontrib-apidoc # BSD
 sphinx>=1.6.2,!=1.6.6,!=1.6.7 # BSD
 openstackdocstheme>=1.18.1 # Apache-2.0