diff --git a/docs/internals.rst b/docs/internals.rst
index aad608dc..18822d47 100644
--- a/docs/internals.rst
+++ b/docs/internals.rst
@@ -288,6 +288,10 @@ All databases are listed, irrespective of user permissions. This means that the
 
 This method lets you read plugin configuration values that were set in ``metadata.json``. See :ref:`writing_plugins_configuration` for full details of how this method should be used.
 
+The return value will be the value from the configuration file - usually a dictionary.
+
+If the plugin is not configured the return value will be ``None``.
+
 .. _datasette_render_template:
 
 await .render_template(template, context=None, request=None)
diff --git a/docs/writing_plugins.rst b/docs/writing_plugins.rst
index 89f7f5eb..9aee70f6 100644
--- a/docs/writing_plugins.rst
+++ b/docs/writing_plugins.rst
@@ -182,6 +182,8 @@ When you are writing plugins, you can access plugin configuration like this usin
 
 This will return the ``{"latitude_column": "lat", "longitude_column": "lng"}`` in the above example.
 
+If there is no configuration for that plugin, the method will return ``None``.
+
 If it cannot find the requested configuration at the table layer, it will fall back to the database layer and then the root layer. For example, a user may have set the plugin configuration option like so::
 
     {