diff --git a/src/gameobjects/group/Group.js b/src/gameobjects/group/Group.js
index 4c3d6d0f0..6373e4b12 100644
--- a/src/gameobjects/group/Group.js
+++ b/src/gameobjects/group/Group.js
@@ -125,7 +125,7 @@ var Group = new Class({
          * The class to create new group members from.
          *
          * @name Phaser.GameObjects.Group#classType
-         * @type {Function}
+         * @type {Phaser.Types.GameObjects.Group.GroupClassTypeConstructor}
          * @since 3.0.0
          * @default Phaser.GameObjects.Sprite
          */
diff --git a/src/gameobjects/group/typedefs/GroupClassTypeConstructor.js b/src/gameobjects/group/typedefs/GroupClassTypeConstructor.js
new file mode 100644
index 000000000..be0aaf77a
--- /dev/null
+++ b/src/gameobjects/group/typedefs/GroupClassTypeConstructor.js
@@ -0,0 +1,10 @@
+/**
+ * @callback Phaser.Types.GameObjects.Group.GroupClassTypeConstructor
+ * @since 3.0.0
+ *
+ * @param {Phaser.Scene} scene - The Scene to which this Game Object belongs.
+ * @param {number} x - The horizontal position of this Game Object in the world.
+ * @param {number} y - The vertical position of this Game Object in the world.
+ * @param {(string|Phaser.Textures.Texture)} texture - The key, or instance of the Texture this Game Object will use to render with, as stored in the Texture Manager.
+ * @param {(string|number)} [frame] - An optional frame from the Texture this Game Object is rendering with.
+ */
diff --git a/src/physics/arcade/PhysicsGroup.js b/src/physics/arcade/PhysicsGroup.js
index f1af33efa..d0013842c 100644
--- a/src/physics/arcade/PhysicsGroup.js
+++ b/src/physics/arcade/PhysicsGroup.js
@@ -103,7 +103,7 @@ var PhysicsGroup = new Class({
          * This should be either `Phaser.Physics.Arcade.Image`, `Phaser.Physics.Arcade.Sprite`, or a class extending one of those.
          *
          * @name Phaser.Physics.Arcade.Group#classType
-         * @type {Function}
+         * @type {Phaser.Types.GameObjects.Group.GroupClassTypeConstructor}
          * @default ArcadeSprite
          * @since 3.0.0
          */