diff --git a/clang/include/clang/Lex/Preprocessor.h b/clang/include/clang/Lex/Preprocessor.h
--- a/clang/include/clang/Lex/Preprocessor.h
+++ b/clang/include/clang/Lex/Preprocessor.h
@@ -729,7 +729,7 @@
   /// Only one of CurLexer, or CurTokenLexer will be non-null.
   std::unique_ptr<Lexer> CurLexer;
 
-  /// The current top of the stack what we're lexing from
+  /// The current top of the stack that we're lexing from
   /// if not expanding a macro.
   ///
   /// This is an alias for CurLexer.