diff --git a/unittests/ExecutionEngine/Orc/QueueChannel.h b/unittests/ExecutionEngine/Orc/QueueChannel.h
index 1528ac94a94..3d1058a83eb 100644
--- a/unittests/ExecutionEngine/Orc/QueueChannel.h
+++ b/unittests/ExecutionEngine/Orc/QueueChannel.h
@@ -14,6 +14,7 @@
 #include "llvm/Support/Error.h"
 
 #include <queue>
+#include <condition_variable>
 
 namespace llvm {