diff --git a/src/problems/vrp.h b/src/problems/vrp.h
index 57a4af8cb..c21e0d15f 100644
--- a/src/problems/vrp.h
+++ b/src/problems/vrp.h
@@ -14,6 +14,7 @@ All rights reserved (see LICENSE).
 #include <mutex>
 #include <numeric>
 #include <ranges>
+#include <semaphore>
 #include <set>
 #include <thread>