diff --git a/include/llvm/ADT/Hashing.h b/include/llvm/ADT/Hashing.h
index 77e6d77b1b8..de56f91eddb 100644
--- a/include/llvm/ADT/Hashing.h
+++ b/include/llvm/ADT/Hashing.h
@@ -53,6 +53,7 @@
 #include <cassert>
 #include <cstring>
 #include <iterator>
+#include <string>
 #include <utility>
 
 namespace llvm {