diff --git a/docs/requirements.txt b/docs/requirements.txt
index 8acece5..7fe681a 100644
--- a/docs/requirements.txt
+++ b/docs/requirements.txt
@@ -17,5 +17,5 @@ six==1.11.0
 sphinx-argparse==0.2.5
 sphinx-rtd-theme==0.4.3
 sqlalchemy==1.2.12
-tornado==4.5.3
+tornado==6.3.2
 traitlets==4.3.2
diff --git a/rtd.requirements.txt b/rtd.requirements.txt
index e28bd36..64d5d48 100644
--- a/rtd.requirements.txt
+++ b/rtd.requirements.txt
@@ -19,5 +19,5 @@ six==1.11.0
 sphinx-argparse==0.2.5
 sphinx-rtd-theme==0.4.3
 SQLAlchemy==1.3.13
-tornado==5.1
+tornado==6.3.2
 traitlets==4.3.2