Reba Heffley was the great-aunt of Greg, Rodrick and Manny. One Christmas, Gammie invited the whole family over, but she forgot Reba. Reba came anyway, but she refused to take off her coat, probably to make everybody else feel guilty. She apparently died in her sleep from unknown causes in Wrecking Ball, according to Frank Heffley.
- Diary of a Wimpy Kid: The Ugly Truth (First appearance)
- Diary of a Wimpy Kid: Wrecking Ball (Flashback)
- In the online book, Aunt Loretta appears instead.
- In Wrecking Ball, she was confirmed to be dead. Her money becomes inheritance that is given to the Heffleys. They use the money to try and build an extension.
- When she died, Greg at first could not remember her because he apparently has lots of great aunts until Susan told him she was the one who used to send him angry letters when he forgot to write thank-you notes for his birthday money.