Rowley Jefferson is Greg's best friend and the deuteragonist of the Diary of a Wimpy Kid series in general. He has had a major role in nearly every book (with the exception of the 9th, 10th, and 12th books). He has overprotective parents who aren't fond of Greg's behavior (specifically Mr. Jefferson, but his mother can seemingly get annoyed by Greg too), assuming that he is a bad influence (which for several reasons he is).
Rowley from all media
Rowley holding a copy of Westmore Warbler (movie)
Rowley posing for his class clown photo.
Rowley's scribbled egg, Rowley Junior.
Rowley as the wingman of Greg.
Rowley gets his tie cut at Corny's.
Rowley gets pantsed by the Mad Pantser.
Rowley with Greg and Chirag.
Greg, and Rowley.
Rowley riding a big-wheel.
Rowley sleeping over with Greg in the Rodrick Rules film.