Evelyn Trimble is a girl who lives in the same neighborhood as Greg and Rowley and is said to be best friends with Victoria Hooks (the younger sister of Latricia Hooks). Evelyn's a strong vampire fanatic and is described to often dress like a vampire--apparently, Evelyn's apparently so obsessed with vampires that Greg thinks that Evelyn probably thinks that she actually is a vampire. Greg says that he and Rowley used to ride the bus with Evelyn, and Greg adds that part of the reason he's thankful that he and Rowley don't take the bus anymore is at least they don't have to deal with Evelyn on the way to and from school.
- Diary of a Wimpy Kid: The Meltdown (First and only appearance)
- She may possibly be related to Julian Trimble.