From Muppet Wiki

Dorothy Gale is the protagonist of L. Frank Baum's novel, The Wizard of Oz. In The Muppets' Wizard of Oz, Dorothy is an aspiring singer who works at the diner owned by Aunt Em.

Other Portrayals

Previously, Miss Piggy had played the role of Dorothy in a sketch in The Muppets Go to the Movies. Baby Piggy played the role in an episode of Muppet Babies and in the book Muppet Babies' Classic Children's Tales.