diff --git a/scene/resources/default_theme/make_header.py b/scene/resources/default_theme/make_header.py
index efad3b2..251104d 100755
--- a/scene/resources/default_theme/make_header.py
+++ b/scene/resources/default_theme/make_header.py
@@ -15,6 +15,9 @@ f = open("theme_data.h", "wb")
 
 f.write(b"// THIS FILE HAS BEEN AUTOGENERATED, DON'T EDIT!!\n")
 
+f.write(b"#ifndef THEME_DATA_GENERATED_H\n")
+f.write(b"#define THEME_DATA_GENERATED_H\n")
+
 # Generate png image block
 f.write(b"\n// png image block\n")
 
@@ -70,4 +73,6 @@ for x in shaders:
     f.write(b'";\n')
     sf.close()
 
+f.write(b"#endif\n")
+
 f.close()
diff --git a/scene/resources/default_theme/theme_data.h b/scene/resources/default_theme/theme_data.h
index 374fd83..b48567c 100644
--- a/scene/resources/default_theme/theme_data.h
+++ b/scene/resources/default_theme/theme_data.h
@@ -1,4 +1,6 @@
 // THIS FILE HAS BEEN AUTOGENERATED, DON'T EDIT!!
+#ifndef THEME_DATA_GENERATED_H
+#define THEME_DATA_GENERATED_H
 
 // png image block
 
@@ -443,3 +445,4 @@ static const unsigned char window_resizer_png[] = {
 };
 
 // shaders block
+#endif