diff --git a/llvm/lib/ExecutionEngine/Orc/Core.cpp b/llvm/lib/ExecutionEngine/Orc/Core.cpp
index 6a0df10f7c3f..e0725730f62b 100644
--- a/llvm/lib/ExecutionEngine/Orc/Core.cpp
+++ b/llvm/lib/ExecutionEngine/Orc/Core.cpp
@@ -15,6 +15,7 @@
 #include "llvm/Support/Debug.h"
 #include "llvm/Support/Format.h"
 
+#include <condition_variable>
 #if LLVM_ENABLE_THREADS
 #include <future>
 #endif