diff --git a/src/core/include/mp-units/ostream.h b/src/core/include/mp-units/ostream.h
index ec30ba669..4b36b0651 100644
--- a/src/core/include/mp-units/ostream.h
+++ b/src/core/include/mp-units/ostream.h
@@ -28,8 +28,8 @@
 #include <mp-units/unit.h>
 
 #ifndef MP_UNITS_IN_MODULE_INTERFACE
-#include <sstream>
 #include <cstdint>
+#include <sstream>
 #endif
 
 namespace mp_units {
diff --git a/src/core/include/mp-units/quantity_spec.h b/src/core/include/mp-units/quantity_spec.h
index c75725b24..5d091b41b 100644
--- a/src/core/include/mp-units/quantity_spec.h
+++ b/src/core/include/mp-units/quantity_spec.h
@@ -37,8 +37,8 @@
 #include <mp-units/dimension.h>
 
 #ifndef MP_UNITS_IN_MODULE_INTERFACE
-#include <tuple>
 #include <cstdint>
+#include <tuple>
 #endif
 
 namespace mp_units {