diff --git a/tasks/prebuild-less-task.coffee b/tasks/prebuild-less-task.coffee
index db9c0ec44..84c365bd1 100644
--- a/tasks/prebuild-less-task.coffee
+++ b/tasks/prebuild-less-task.coffee
@@ -19,10 +19,16 @@ module.exports = (grunt) ->
         path.resolve('static')
         path.resolve('vendor')
       ]
+      themeMains = []
       for theme in configuration
         # TODO Use AtomPackage class once it runs outside of an Atom context
-        themePath = path.resolve('node_modules', theme, 'stylesheets')
-        importPaths.unshift(themePath) if grunt.file.isDir(themePath)
+        themePath = path.resolve('node_modules', theme)
+        stylesheetsDir = path.join(themePath, 'stylesheets')
+        {main} = grunt.file.readJSON(path.join(themePath, 'package.json'))
+        main ?= 'index.less'
+        mainPath = path.join(themePath, main)
+        themeMains.push(mainPath) if grunt.file.isFile(mainPath)
+        importPaths.unshift(stylesheetsDir) if grunt.file.isDir(stylesheetsDir)
 
       grunt.log.writeln("Building LESS cache for #{configuration.join(', ').yellow}")
       lessCache = new LessCache
@@ -33,3 +39,7 @@ module.exports = (grunt) ->
       for file in @filesSrc
         grunt.log.writeln("File #{file.cyan} created in cache.")
         lessCache.readFileSync(file)
+
+      for file in themeMains
+        grunt.log.writeln("File #{file.cyan} created in cache.")
+        lessCache.readFileSync(file)