Trista

Trista is a girl and supporting character in the series who met Greg and Rowley at the end of The Last Straw. They took her to Rowley's dad's Country Club in Dog Days. In Dog Days, she went to the country club with Greg and Rowley but within five minutes, she met a life guard, hung out with him for the rest of the time, and forgot all about Greg and Rowley. This causes Greg to disregard her.

Trivia

 * Which state Trista moved from remains unknown, though in the online book, Greg notes down that Trista came from New Mexico.
 * In the Diary of a Wimpy Kid: The Ugly Truth, she is confirmed to be Greg's girlfriend.