|Actor||A Juliana Pig|
The Pig is a pig owned by the Heffley Family was introduced in Diary of a Wimpy Kid: The Long Haul. It seems that he is only fond of Manny, just like how Sweetie is only fond of Susan and Gramma. The pig is the second farm animal won by the Heffleys after a goat (mentioned in Diary of a Wimpy Kid: Cabin Fever). which was won by Greg for correctly guessing a goat's weight, but Frank didn't let them keep him. Just like that case, Frank didn't want to keep the pig, but Susan said she couldn't return him, because the pig seemed to be "imprinted" on Manny. Rodrick also agreed to keep the pig, as he thought you could get bacon from him every morning the way you get eggs from a chicken (which wouldn't make sense in real life). As of The Meltdown, the pig has escaped after being sent to obedience school by Frank and no longer lives with the Heffleys. It was played by a Juliana Pig in the film.
The Long Haul
While going to the state fair, Susan and Manny went to a tent where it had a contest of guessing the correct weight for the pig. That was when Greg was looking out for the Beardos, and Manny won the contest, and the prize was a real-life baby pig. However, Susan refused, saying that they just entered the contest for fun and did not want the pig; however, the people were insulted and forced her to keep it.
The pig caused trouble for the Heffleys. He tried to escape out of the cooler and the car. Fortunately, he was saved before he became roadkill. They tried to bring him into the second hotel they stayed at by hiding him in the cooler. While there, he caused a mess in one of the bathrooms and ate all the food in both of the minibars, which made the Heffleys pay extra for the minibar's snack and for violating the no-pet rule. Later, while in the van, he woke up and caused chaos, which resulted in Greg getting bitten by the pig. Because of all that, Susan put the pig in a petting zoo. Manny was heartbroken by the news, while the Heffleys took Greg to a vet to check Greg's bitten finger. The Heffleys came back for the pig later when they were aided by two Spanish men and Manny. At home, Susan managed to teach him some tricks.
Greg says that Susan would reward the pig with a cookie every time he stood on his hind legs. Since then, the pig had learned to walk on his back legs and never walks on all four feet. Greg then talks about how he doesn't wear collars or leashes because he thinks he is too good for them, also pointing out how he didn't know how the pig had managed to do it without thumbs and now had a pair of pants which is put on by Manny. The pig is able to walk into the open world to the content of his heart, with the addition that he does not have a curfew, unlike Greg. It is possible that the pig might have learned to write, as Greg seemingly gets a letter from the pig during his trip to Hardscrabble Farms. However, this could have been a prank set by one of the family members.
Greg said that the pig figured out how to use the See-and-Talk and can make him say almost full sentences. After Greg finishes his chores, he decides to help himself to a piece of candy corn, which he won in a contest. He comes up into his room to discover that the pig had eaten all of the candy corn, and found a way to open it. At first, Greg is angry with the pig, but when it started looking sick, Greg worries and calls Rodrick to help him. Rodrick tries to drive the pig to the vet, but before they get there, the pig throws up in the van. Since it was Greg's fault that the pig threw up, Rodrick makes Greg clean up the mess. He tries but is totally grossed out by the vomit, that he throws up himself. Unfortunately, a lady raking the leaves witnessed the whole thing and calls the cops. Greg explains to the cops what happened. When Rodrick and Greg finally start driving, Susan catches them, and as punishment, Greg has to take three chores out of the Grab Bag. The pig is later seen eating gummy worms when Greg tries to film a movie.
After the pig getting mad about not going on the Heffley's vacation to Isla de Corales during The Getaway (due to him feeling he was part of the family), Frank sends him to obedience school, but the next day Frank gets a call from the person who runs the place saying that the pig had escaped. Greg and his family puts up posters to find him but is unsuccessful. At the end of the book, Greg says he thinks the pig is somewhere warm.
One of Manny's stuffed animals in the stuffed toy pile references the pig. It is also possible that this is the pig and Manny has been caring for him in secret.
The Deep End
The pig made a cameo appearance as one of the animals drowning when Greg was talking about Noah's Ark.
The pig is surprisingly super smart. He somehow opened three cans of soda, can use the TV remote to watch television with Manny, and was able to remove his GPS collar soon after being put on him, despite not having fingers. That made Greg feel annoyed. The pig also can walk on two legs, refuses to wear a leash, and eats at the dinner table. The pig also occasionally wears a pair of Manny's shorts which Manny put on him.
- Diary of a Wimpy Kid: The Long Haul
- Diary of a Wimpy Kid: Old School
- Diary of a Wimpy Kid: Double Down
- Diary of a Wimpy Kid: The Meltdown (flashback)
- Happy Meal Commercial
- Diary of a Wimpy Kid: The Long Haul (Film) 
- Diary of a Wimpy Kid: Wrecking Ball (likeness)
- Diary of a Wimpy Kid: The Deep End (imagined)
- He is a domesticated pig, as he is from the livestock of a farm.
- In The Wimpy Kid Movie Diary: The Next Chapter, it was shown it was played by a Juliana Pig.
- The name of the pig is currently unknown. It is also unknown if he has been named or not, but he was named "Junior" in the Spanish version of the books.
- He wears shorts as revealed in Old School. However, he does not wear it in Double Down and Diary of a Wimpy Kid: Old School, maybe because it managed to take it off.
- He eats at the dinner table, to Greg's disapproval.
- For a while, after Susan taught him to walk on two legs, he went through a phase of only walking like that. However, in Double Down, he goes back to walking on all fours.
- In Cabin Fever, Greg won a goat in a similar competition, but Frank refused to take the goat as his pet. This can be explained because the fair people let them not keep the goat but didn't let them not keep the pig.
- He might be able to write letters as seen on page 172 of Diary of a Wimpy Kid: Old School when Greg talks about his mail; though this is most likely a prank from Rodrick, who sent him candy wrappers of Greg's.
- He doesn't wear leashes or collars, because he supposedly thinks he is too good for them. Furthermore, he is capable of taking a leash off of him and grabbing things despite lacking thumbs.
- There are no instances of Greg talking about or even introducing the pig to his best friend Rowley. In Diary of a Wimpy Kid: Old School Greg calls him to his house to inform him about his lemonade selling plan, and they were inside the house for a while because of the heat. Even so, there was no incident of Rowley with the pig. In addition, Rowley doesn't mention the Pig at all in Diary of an Awesome Friendly Kid.
- Out of all the characters introduced, the pig seems to be the most unrealistic, as pigs cannot learn how to walk on their hind legs, due to their bone structure similar to that of dogs (there has only been one pig in the history of the world who currently resides in China who can walk on his front legs for the whole time, which was harmful for their backbone if it's in real life). Pigs cannot write for obvious reasons; however, the writing part was probably a prank or a made-up.
- He once wore a collar, but he threw it out in about 5 minutes after thinking he was too good for it.
- The pig appears to be super smart since he can walk on two feet, can use the T.V. remote, can remove his G.P.S. collar despite not having fingers, supposedly thinks he is too good for leashes and wears a pair of Manny's pants given to him from Manny. It is also possible the pig can write as shown on Page 172 of Diary of a Wimpy Kid: Old School. The pig also learned to use Manny‘s potty as shown in the book Diary of a Wimpy Kid: The Long Haul when he goes to the bathroom despite no explanation that he's been trained too.
- The pig's ascension to being human-like may be a reference to Animal Farm.
- This is not very unusual because pigs are actually intelligent animals.
- His name might be "Junior" according to a Twitter post by the series author, Jeff Kinney. He explained that the pig's name might really be named "Junior" in the series Spanish translation.
- The pig did not appear in Diary of a Wimpy Kid: The Getaway. However, he did appear in The Meltdown, but only in a flashback--it's explained in the previous book, that the family left the pig in a kennel while they were on vacation. He got mad and disappointed when they came back and after being sent to obedience school, he ran away.
- Surprisingly despite imprinting with Manny, in the Meltdown after running away Manny doesn't seem that concerned with the Pig being lost. In fact, Susan seems more distraught about losing the Pig than Manny.
- The Pig made an appearance in a Happy Meal Commercial created McDonald's alongside Greg Rodrick, Gammie, and Sweetie.
- The Pig's top art drawing can be seen as a sign named "All yeh can eat buffet" in Corny's restaurant.
- It's unknown if the pig will appear in any future installments of the series, due to him running away. It is most likely he won’t appear again, due to how badly he was received by fans.
- It is revealed by Jeff Kinney that the pig is a replacement for Sweetie, because Jeff wanted to keep Sweetie around more. However, Sweetie still makes cameos.
- A pig very reminiscent to the pig is shown as an animal on Noah's Ark in The Deep End. The Pig also appears in a Target exclusive mini-poster of the book.
- The Heffleys' Pig is seen in multiple scenes in the preview of Diary of a Wimpy Kid: The Long Haul (film)