diff --git a/requirements.txt b/requirements.txt
index 431f0df..340c75a 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -70,7 +70,7 @@ Send2Trash==1.5.0
 six==1.12.0
 terminado==0.8.2
 testpath==0.4.4
-tornado==6.0.3
+tornado==6.3.3
 tqdm==4.37.0
 traitlets==4.3.3
 typed-ast==1.4.0