<Li> Bill Irwin as Lou Lou Who, Cindy Lou's loving father and the postman of Whoville . </Li> <Li> Molly Shannon as Betty Lou Who, Cindy Lou's mother and a rival to Martha May in a house - lighting contest . </Li> <Li> Kelley as Max, who is The Grinch's pet dog and only companion on Mt . Crumpit . It is unknown how or when The Grinch got him . <Ul> <Li> Frank Welker as the voice of Max </Li> </Ul> </Li> <Ul> <Li> Frank Welker as the voice of Max </Li> </Ul>

Who plays max in how the grinch stole christmas