diff --git a/lib/core/include/internal/comparators.h b/lib/core/include/internal/comparators.h
index 57e3f14..3486f80 100644
--- a/lib/core/include/internal/comparators.h
+++ b/lib/core/include/internal/comparators.h
@@ -17,6 +17,8 @@
 
 #pragma once
 
+#include <cstdint>
+
 #include "polymake/internal/comparators_ops.h"
 #include "polymake/internal/matrix_rows_cols.h"
 #include "polymake/TransformedContainer.h"