diff --git a/util/thread_local.h b/util/thread_local.h
index 3adf8ba85..b15c6f25b 100644
--- a/util/thread_local.h
+++ b/util/thread_local.h
@@ -10,6 +10,7 @@
 #pragma once
 
 #include <atomic>
+#include <functional>
 #include <memory>
 #include <unordered_map>
 #include <vector>