diff --git a/sphinx/config.py b/sphinx/config.py
index 99c32226f..1d0f1085e 100644
--- a/sphinx/config.py
+++ b/sphinx/config.py
@@ -38,7 +38,7 @@ class Config(object):
         unused_docs = ([], True),
         exclude_dirs = ([], True),
         exclude_trees = ([], True),
-        exclude_dirnaems = ([], True),
+        exclude_dirnames = ([], True),
         default_role = (None, True),
         add_function_parentheses = (True, True),
         add_module_names = (True, True),