diff --git a/src/libslic3r/GCode/GCodeProcessor.hpp b/src/libslic3r/GCode/GCodeProcessor.hpp
index 19ff0f8cb..8d5aa3df8 100644
--- a/src/libslic3r/GCode/GCodeProcessor.hpp
+++ b/src/libslic3r/GCode/GCodeProcessor.hpp
@@ -10,6 +10,7 @@
 #include <cstdint>
 #include <array>
 #include <vector>
+#include <mutex>
 #include <string>
 #include <string_view>
 #include <optional>