diff --git a/iwyu_preprocessor.cc b/iwyu_preprocessor.cc
index a129f05..a17d4ec 100644
--- a/iwyu_preprocessor.cc
+++ b/iwyu_preprocessor.cc
@@ -44,7 +44,6 @@ using clang::SourceLocation;
 using clang::SourceRange;
 using clang::Token;
 using llvm::errs;
-using llvm::Optional;
 using llvm::StringRef;
 using std::make_pair;
 using std::string;