Rowley Jefferson- Greg's best friend who he often fights with. Greg is always trying to convince Rowley to do things they know they shouldn't be doing like watching scary movies or going on a scary ride at an amusement park.
Rodrick Heffley- Rodrick is Greg's older brother and is often considered to be the antagonist of the books. He is often trying to get Greg to do things for him or pulling pranks on him.
Manny Heffley- Manny is Greg's little brother. Manny is very spoiled by his mother and is never in trouble; anything he ever does wrong is often considered cute.
Patty Farrell- Greg considers Patty to be his arch enemy at school. She is often bullying him and trying to make him look bad in front of their classmates.
Holly Hill- Holly is the new student in school in Diary of a Wimpy Kid: Rodrick Rules. Greg quickly develops a crush on Holly and is always trying to impress her.
