diff --git a/Core/src/Utilities/BinningType.cpp b/Core/src/Utilities/BinningType.cpp
index dd0295881a9..08a3dd58ce5 100644
--- a/Core/src/Utilities/BinningType.cpp
+++ b/Core/src/Utilities/BinningType.cpp
@@ -9,6 +9,7 @@
 #include "Acts/Utilities/BinningType.hpp"
 
 #include <algorithm>
+#include <ostream>
 #include <stdexcept>
 
 namespace Acts {