diff --git a/src/nbsphinx.py b/src/nbsphinx.py
index 1ea3e861..661963e6 100644
--- a/src/nbsphinx.py
+++ b/src/nbsphinx.py
@@ -284,7 +284,7 @@
 .. raw:: html
 
     <script type="application/vnd.jupyter.widget-state+json">
-    {{ nb.metadata.widgets['application/vnd.jupyter.widget-state+json'] | json_dumps }}
+    {{ nb.metadata.widgets['application/vnd.jupyter.widget-state+json'] | json_dumps | escape_html_script }}
     </script>
 {% endif %}
 {{ super() }}