diff --git a/src/readium/config.py b/src/readium/config.py
index cbb81a5..57e1313 100644
--- a/src/readium/config.py
+++ b/src/readium/config.py
@@ -140,6 +140,7 @@
     ".conf",
     ".json",
     ".xml",
+    ".ipynb",
 }
 
 MARKITDOWN_EXTENSIONS = {