diff --git a/lib/AST/NameLookup.cpp b/lib/AST/NameLookup.cpp
index 4beeae0d0ef00..c59173d0413b9 100644
--- a/lib/AST/NameLookup.cpp
+++ b/lib/AST/NameLookup.cpp
@@ -3297,7 +3297,7 @@ createExtensionGenericParams(ASTContext &ctx,
 }
 
 /// If the extended type is a generic typealias whose underlying type is
-/// a tuple, the extension inherits the generic paramter list from the
+/// a tuple, the extension inherits the generic parameter list from the
 /// typealias.
 static GenericParamList *
 createTupleExtensionGenericParams(ASTContext &ctx,