diff --git a/llvm/include/llvm/Support/SwapByteOrder.h b/llvm/include/llvm/Support/SwapByteOrder.h
index 8f26af6f68ac65..18fd41ac5b04e4 100644
--- a/llvm/include/llvm/Support/SwapByteOrder.h
+++ b/llvm/include/llvm/Support/SwapByteOrder.h
@@ -15,7 +15,6 @@
 #define LLVM_SUPPORT_SWAPBYTEORDER_H
 
 #include "llvm/ADT/bit.h"
-#include <cstddef>
 #include <cstdint>
 #include <type_traits>