diff --git a/extensions/glsl/languages/glsl/highlights.scm b/extensions/glsl/languages/glsl/highlights.scm
index 9f0754b61ed2f8a596e186063224499f2afd1188..0509d0f5ef00977a8f809baa4684a09628dd0172 100644
--- a/extensions/glsl/languages/glsl/highlights.scm
+++ b/extensions/glsl/languages/glsl/highlights.scm
@@ -57,7 +57,7 @@
   (system_lib_string)
 ] @string
 
-(null) @constant
+(null) @constant.builtin
 
 [
   (number_literal)