diff --git a/tljh/installer.py b/tljh/installer.py
index 3c8f22299..0df17e1c9 100644
--- a/tljh/installer.py
+++ b/tljh/installer.py
@@ -195,7 +195,7 @@ def ensure_jupyterhub_package(prefix):
         'jupyterhub-firstuseauthenticator==0.12',
         'jupyterhub-nativeauthenticator==0.0.4',
         'jupyterhub-ldapauthenticator==1.2.2',
-        'oauthenticator==0.8.0',
+        'oauthenticator==0.8.0'
     ])
     traefik.ensure_traefik_binary(prefix)
 
@@ -252,7 +252,9 @@ def ensure_user_environment(user_requirements_txt_file):
         # nbresuse to show people how much RAM they are using
         'nbresuse==0.3.0',
         # Most people consider ipywidgets to be part of the core notebook experience
-        'ipywidgets==7.4.2'
+        'ipywidgets==7.4.2',
+        # Pin tornado
+        'tornado<6.0'
     ])
 
     if user_requirements_txt_file: