Patty Farrell is a girl in Greg's grade who has a "nerd" look and always is a major tattletale to Greg. In the first book, Greg finds a way to cheat on his USA state capitals test by sitting near to the USA map, but Patty ruins it by telling the teacher to cover the USA map and causes Greg to fail the test. She plays Dorothy in the school musical the Wizard of Oz and apples get thrown at her by the trees (including Greg). In The Last Straw, when the teacher leaves the room, Patty is left in charge and when she is in charge, she lets no one out of the room, even when they have to use the bathroom.