diff --git a/doc/conf.py b/doc/conf.py
index 654040c95b1c..80282c70a7bb 100644
--- a/doc/conf.py
+++ b/doc/conf.py
@@ -682,7 +682,10 @@ def linkcode_resolve(domain, info):
                     if lineno else "")
 
         startdir = Path(matplotlib.__file__).parent.parent
-        fn = os.path.relpath(fn, start=startdir).replace(os.path.sep, '/')
+        try:
+            fn = os.path.relpath(fn, start=startdir).replace(os.path.sep, '/')
+        except ValueError:
+            return None
 
         if not fn.startswith(('matplotlib/', 'mpl_toolkits/')):
             return None