diff --git a/INSTALL.rst b/INSTALL.rst
index cae1500e..08d49e23 100644
--- a/INSTALL.rst
+++ b/INSTALL.rst
@@ -49,6 +49,11 @@ If you now connect to port 8080 and log in with username 'grok',
 password 'grok', you should be able to add the grok-based applications
 (such as grokwiki) from the menu.
 
+If you are using python >= 3.13 and encounter a ``No module named 'cgi'``
+error, install the legacy cgi package:
+
+    $ bin/pip install legacy-cgi
+
 Running the tests
 -----------------