diff --git a/doc/api.rst b/doc/api.rst
index 331d08868..e17e468a6 100644
--- a/doc/api.rst
+++ b/doc/api.rst
@@ -300,7 +300,7 @@ Utility methods
 .. automodule:: message_ix.util
    :members: expand_dims, copy_model, make_df
 
-.. automodule:: message_ix.util.Sankey
+.. automodule:: message_ix.util.sankey
    :members: map_for_sankey
 
 Testing utilities