diff --git a/packages/display/src/DisplayObject.js b/packages/display/src/DisplayObject.js
index 3a701f9..1f9a6c6 100644
--- a/packages/display/src/DisplayObject.js
+++ b/packages/display/src/DisplayObject.js
@@ -152,7 +152,7 @@
         /**
          * The original, cached mask of the object.
          *
-         * @member {PIXI.Graphics|PIXI.Sprite}
+         * @member {PIXI.Graphics|PIXI.Sprite|null}
          * @protected
          */
         this._mask = null;
@@ -680,7 +680,7 @@
      * sprite.mask = graphics;
      * @todo At the moment, PIXI.CanvasRenderer doesn't support PIXI.Sprite as mask.
      *
-     * @member {PIXI.Graphics|PIXI.Sprite}
+     * @member {PIXI.Graphics|PIXI.Sprite|null}
      */
     get mask()
     {