diff --git a/requirements.txt b/requirements.txt
index 0444e0bb5..4199427eb 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -7,6 +7,7 @@ Babel>=2.3.4 # BSD
 itsdangerous<2.1 # BSD
 Flask!=0.11,<1.0,>=0.10 # BSD
 iso8601>=0.1.11 # MIT
+Jinja2<3.1.0 # BSD
 jsonschema>=2.0.0,<3.0.0,!=2.5.0 # MIT
 oslo.config>=3.22.0 # Apache-2.0
 oslo.i18n>=2.1.0 # Apache-2.0