diff --git a/requirements.txt b/requirements.txt
index eeb2c4f992..a12930b1a6 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -15,4 +15,4 @@ Pygments==2.5.2
 pymdown-extensions==9.0
 PyYAML==5.3
 six==1.14.0
-tornado==6.0.3
+tornado==6.3.3