diff --git a/src/libslic3r/Format/ModelIO.hpp b/src/libslic3r/Format/ModelIO.hpp
index a0751f2d96..0d335c7958 100644
--- a/src/libslic3r/Format/ModelIO.hpp
+++ b/src/libslic3r/Format/ModelIO.hpp
@@ -1,3 +1,5 @@
+#pragma once
+
 #include <string>
 
 namespace Slic3r {
diff --git a/src/libslic3r/QuadricEdgeCollapse.hpp b/src/libslic3r/QuadricEdgeCollapse.hpp
index c7330bfc5f..3da59c20e9 100644
--- a/src/libslic3r/QuadricEdgeCollapse.hpp
+++ b/src/libslic3r/QuadricEdgeCollapse.hpp
@@ -1,3 +1,5 @@
+#pragma once
+
 // paper: https://people.eecs.berkeley.edu/~jrs/meshpapers/GarlandHeckbert2.pdf
 // sum up: https://users.csc.calpoly.edu/~zwood/teaching/csc570/final06/jseeba/
 // inspiration: https://github.com/sp4cerat/Fast-Quadric-Mesh-Simplification
diff --git a/src/slic3r/GUI/InstanceCheckMac.h b/src/slic3r/GUI/InstanceCheckMac.h
index 0af2737efb..e0ee9191f2 100644
--- a/src/slic3r/GUI/InstanceCheckMac.h
+++ b/src/slic3r/GUI/InstanceCheckMac.h
@@ -1,3 +1,5 @@
+#pragma once
+
 #import <Cocoa/Cocoa.h>
 
 @interface OtherInstanceMessageHandlerMac : NSObject
diff --git a/src/slic3r/GUI/PartSkipDialog.hpp b/src/slic3r/GUI/PartSkipDialog.hpp
index 4e4f7b6bb6..cb65a3f2e7 100644
--- a/src/slic3r/GUI/PartSkipDialog.hpp
+++ b/src/slic3r/GUI/PartSkipDialog.hpp
@@ -1,3 +1,5 @@
+#pragma once
+
 #include "slic3r/GUI/wxExtensions.hpp"
 #include <map>
 #include <cstdint>
diff --git a/src/slic3r/GUI/RemovableDriveManagerMM.h b/src/slic3r/GUI/RemovableDriveManagerMM.h
index 71239dba32..6f5299111c 100644
--- a/src/slic3r/GUI/RemovableDriveManagerMM.h
+++ b/src/slic3r/GUI/RemovableDriveManagerMM.h
@@ -1,3 +1,5 @@
+#pragma once
+
 #import <Cocoa/Cocoa.h>
 
 @interface RemovableDriveManagerMM : NSObject
diff --git a/src/slic3r/GUI/Widgets/TextCtrl.h b/src/slic3r/GUI/Widgets/TextCtrl.h
index f616b177f0..777cd31887 100644
--- a/src/slic3r/GUI/Widgets/TextCtrl.h
+++ b/src/slic3r/GUI/Widgets/TextCtrl.h
@@ -1,3 +1,5 @@
+#pragma once
+
 #include <wx/textctrl.h>
 #include <wx/colour.h>