|Actor||June Foray (voice only in Class Clown short)
Unknown actor in The Deep End trailer
|Film Appearance?||Yes (Bonus feature only)|
|Online Appearance?||No (possibly as Aunt Mary-Lou)|
Gammie Heffley is Greg, Rodrick, and Manny's paternal great-grandmother of around 95. She is the grandmother of Frank, Joe and Gary Heffley and the mother of Grandpa Heffley. She is the oldest living member of the Heffley family and the widow of Greg's late great-grandpa Chester.
Gammie has a lot of wisdom and traditionally gives "The Talk" to her older grandchildren and great-grandchildren on the edge of becoming teenagers. Gammie likes visitors, as she often makes meals for them and she also likes to make people feel guilty, as shown when Greg puts a whoopee cushion under her chair and several days later, she sends a handwritten apology to everyone in the family.
Role in The Ugly Truth
Gammie first appears in The Ugly Truth when Greg mentions that the reception for Uncle Gary's fourth wedding will be at Gammie's House. He then goes on to talk about how Gammie is like the head of the whole Heffley Family. Greg says that Gammie is one of the only people in the world who still writes letters. Greg has tried to explain to Gammie that kids don't know how to write letters so Gammie gave him a starter letter with all the information on it so that Greg wouldn't have any excuse not to write. However, Greg hadn't written the letter and it sits on his desk in his bedroom.
Greg also writes about how in the last Thanksgiving, he put a whoopee cushion on her chair and she wrote a hand written apology to everyone in the entire family. He also says on the previous Easter, nobody went to Gammie's house even though she invited them. On Easter Sunday, she called Dad and told him that she won the lottery and everyone in the family went to her house. However, the scratch card was not a winner but Gammie had made ham 'in case anyone stopped by', meaning that she got what she really wanted. Greg writes about how it is his turn to get 'The Talk' next time the family goes to Gammie's house.
When it is time for Uncle Gary's wedding, the family stays at Gammie's house. People have been writing their names on sticky-notes and putting them on all of Gammie's stuff so that they can claim it when she dies. Greg thinks that this is disrespectful, even though he has done it once or twice. During the night, Greg gets fed up of sleeping in the Bachelors' room so he sleeps in Gammie's bathroom, and wakes up just in time before Gammie has a bath.
After the wedding, Greg goes to get 'The Talk' with Gammie, who tells him that he shouldn't be in a rush to grow up. However, Greg excuses himself after Gammie starts rolling down one of her socks.
Role in Cabin Fever
Role in The Deep End
She reappears in The Deep End when she calls Dad to ask him to move Uncle Gary's RV, which had been parked in her driveway for two years. After taking the RV, Gammie makes the family some sandwiches before they go on their roadtrip. In The Deep End trailer, Gammie joins the video call along with everyone else and can be heard asking if she is on mute.
- Gammie is one of the few characters in the series to have a confirmed age of 95. She would, therefore, be born around 1914.
- According to the family tree in the original version of "The Wimpy Kid Do-It-Yourself Book", Gammie is on Susan's side of the family (as Grampa's mother). However, when she later appeared in "The Ugly Truth", she was said to be on Frank's side instead, meaning she is either Grandpa or Nana's mother.
- In a flashback in Diary of a Wimpy Kid: Cabin Fever, when Greg sneaks into his mother's, email account to tell everyone to coordinate all of the Christmas presents he will get, Gammie's name can be seen on the computer.
- Gammie made an appearance in a McDonald's Happy Meal Commercial alongside The Pig, Rodrick, and Sweetie.
- Gammie is the main antagonist of the Ugly Truth.
- Gammie could be the book counterpart of Mary-Lou, due to them looking very similar.
- The only book Gammie has a major role in is the Ugly Truth. After that, she only appears in short films, the Do It Yourself Book, and as a cameo in The Deep End.
- Diary of a Wimpy Kid: The Ugly Truth (First appearance)
- Diary of a Wimpy Kid: Cabin Fever (Mentioned)
- Diary of a Wimpy Kid: Class Clown
- Happy Meal Commercial
- The Wimpy Kid: Do it Yourself Book
- Diary of a Wimpy Kid: The Long Haul (film)
- Diary of a Wimpy Kid: The Deep End