diff --git a/Dockerfile b/Dockerfile
index 2e5c59e10450743a12d97c79151fe266f2727278..d566a9cb4520cc1657c6c9927cfb49cee967d14b 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -79,7 +79,9 @@ RUN curl -O https://bootstrap.pypa.io/get-pip.py && \
     python3 get-pip.py && \
     rm get-pip.py
 
+# Force tornado 5 as version 6 breaks jupyter
 RUN pip3 --no-cache-dir install \
+            'tornado==5.1.1' \
             'notebook==5.7.4' \
             'jupyterhub==0.9.4' \
             'jupyterlab==0.35.4' \