|Online Appearance?||Yes (as Lori Matthews)|
Heather Hills is a teenager in Rodrick Heffley's grade and is Holly Hills' older sister. Greg had a big crush on her in the book version and is Rodrick's love interest and one of the main antagonists in the third film.
Heather has a huge resemblance on her sister Holly Hills, has long hair, which she sometimes set as a pony tail and wears black earrings in both of her ears.
In Rodrick Rules, she babysits Rowley while his parents were gone. Greg harbors a crush on her. Whenever Rowley's parents go out, Greg would go to Rowley's house at 8:00 PM and splash on Rodrick's Cologne to make sure he makes a good impression on her. She was later replaced by Leland, which surprised Greg and started complaining how his parents needed to keep Heather. In the 2nd film she is shown as Rodrick's girlfriend at his party. She is also mentioned by Holly. Holly shows that Heather is a female version of Rodrick, like how Greg is possibly Holly's female counterpart. Also, she appears in Rodrick's old yearbook.
In Dog Days, Greg has a crush on both her and her sister Holly and thinks of getting good with her because he wants to have a high school girlfriend before the school starts. He finds out she is a lifeguard at the pool by looking into one of the family's summer albums. When the family went the pool, Greg went into the bathroom and started doing push-ups and other exercises so his muscles pop-up then he goes near her chair. Whenever a kid does something bad, Greg spoke up before Heather could say anything, thinking it will impress her. But then, a kid vomited and Greg didn't clean up, which was the only time when she payed attention to Greg because she was expecting him to say it. The other day when Greg came there, he went near her chair and asked Susan take a picture of him there. Susan was about to take the picture, but she got a phone call from a old friend. By the time she takes the photo, Heather left so Greg ended having the photo taken with another Lifeguard. Greg then realized she is going to college, he thought long-term relationships don't work so he scrapped his plan of getting good with her.
Heather is only briefly mentioned in Diary of a Wimpy Kid: Rodrick Rules (film) and is described by Holly as a female equivalent of Rodrick.
In the book series Greg has a huge crush on her, but in the movie he hates her and also describes her as "Rodrick in a dress".
She later appears in the third film as a love interest of Rodrick and one of the main antagonists, acting like a bigger jerk than Rodrick, being a stereotypical self centered teenage girl. She first shows up to pick Holly from school, and when Rodrick tries to flirt with her, she runs over his foot. She naturally goes to the same Country Club as her family, getting a job there as a life guard. She acts rude to almost everyone, including her own parents, only thinking about her upcoming sweet sixteen and even ignores when Rodrick pretends to drown to get her attention. Greg manages to get her to hire Loded Diper for her birthday. While there, it falls into ruins when she angrily reacts to Rodrick's rock cover of Justin Bieber's "Baby." Just then, Rodrick accidentally knocks down the ice sculpture, making her angry and trying to hit Rodrick but he dodged and hit the chocolate fountain causing it to spray and all the guests left her party. Greg apologized to Holly, but she said she was happy and that she thought that Heather fairly deserved it.
in the online book her name is "Lori Matthews" and is the oldest of the four Matthews sisters in the Matthews Family, she also just like the book babysitted Rowley, however she was fired for smoking after putting Rowley to bed, it also hints that she smokes. Greg says that she is the prettiest of the Matthews sisters, but then Greg later says Piper Matthews is the most prettiest.
- In the online book, she is known as "Lori Matthews". It is shown at Day 124.
- Heather is shown to be hot-tempered in the film series, but in the books she makes too little appearances to know what her personality is like in them.
- Why Heather was replaced by Leland is unknown, but in the online book, it states that she was fired for smoking outside Rowley's house after she had put him to bed.
- Rodrick's girlfriend in the second film was played by Melissa Roxburgh, so it may be possible that Heather Hills was Rodrick's girlfriend in the second film.
- They never dated and it is a one-sided relationship on Rodrick, since Heather is not interested in him. Because she thinks of him as a loser.
- In the end of the Dog Days film it is revealed that Heather's age is 16.