Erika Hernadez is a girl in Greg's grade, who only appeared in The Third Wheel. She is said to have dumped her boyfriend, Jamar Law after he became famous for getting his head stuck in a chair. Greg thought of going to the Valentine's Day Dance with her, but was worried that he would keep on thinking about what happened to Jamar, and would never be able to get past it.
- Described by Greg as "pretty and nice". Otherwise, personality is unknown.
- Diary of a Wimpy Kid: The Third Wheel (First and only appearance)