diff --git a/build/Gruntfile.coffee b/build/Gruntfile.coffee
index 7c687ac92..1a34b70f2 100644
--- a/build/Gruntfile.coffee
+++ b/build/Gruntfile.coffee
@@ -128,7 +128,7 @@ module.exports = (grunt) ->
       lessConfig.glob_to_multiple.src.push("#{directory}/**/*.less")
       prebuildLessConfig.src.push("#{directory}/**/*.less") unless theme
       csonConfig.glob_to_multiple.src.push("#{directory}/**/*.cson")
-      pegConfig.glob_to_multiple.src.push("#{directory}/**/*.pegjs")
+      pegConfig.glob_to_multiple.src.push("#{directory}/lib/*.pegjs")
 
   grunt.initConfig
     pkg: grunt.file.readJSON('package.json')