diff --git a/requirements.txt b/requirements.txt
index 7796111..b3fa0ca 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -6,4 +6,4 @@ MarkupSafe==1.1.1
 mkdocs==1.2.3
 PyYAML==5.4
 six==1.12.0
-tornado==6.0.3
+tornado==6.3.3