diff --git a/doc/requirements.txt b/doc/requirements.txt
index 53f48858..cb87a923 100644
--- a/doc/requirements.txt
+++ b/doc/requirements.txt
@@ -2,3 +2,4 @@ sphinx>=1.6.2
 sphinx_rtd_theme==0.2.4
 falcon==1.4.1
 oslo.config==7.0.0
+markupsafe==2.0.1