Diary of a Wimpy Kid: Partypooper

Author	Jeff Kinney
Illustrator	Jeff Kinney Chad W. Beckerman
Publisher	Abrams Books (Amulet Books) (US) Penguin Books (Puffin Books) (UK)
Release date	October 21, 2025
Pages	224 (217 reading pages)
ISBN	978-1419782695
Book number	20
Color	Pink with birthday cake texture And decorations
Preceded by	Diary of a Wimpy Kid: Hot Mess
Followed by	Diary of a Wimpy Kid: Book 21 (unconfirmed)

Diary of a Wimpy Kid: Partypooper is the upcoming 20th book in the Diary of a Wimpy Kid series. It will release on October 21, 2025. Jeff Kinney has stated on Twitter that "There will be at least 20 books in the series." meaning that this will likely not be the final book. Alongside this, in a TikTok Live, Jeff Kinney himself stated that he was contractually obligated to make a minimum of 20 books.

The cover shows Greg inside a large cake that is being consumed by him and Manny Heffley, with both of them wearing striped birthday hats. A teaser cover for the book was revealed on February 10th, 2025 and the cover was revealed on February 27, 2025.

Characters

Main

• Greg Heffley
• Rodrick Heffley
• Manny Heffley
• Susan Heffley
• Frank Heffley
• Rowley Jefferson (possibly)

Synopsis

International bestselling author Jeff Kinney serves up heaps of laughs in Partypooper, the 20th book in the Diary of a Wimpy Kid series.

You’re Invited—RSVP for Fun!

Over the years, Greg Heffley has chronicled his mishaps and misadventures in a series of diaries—make that journals—but book 20 of the Diary of a Wimpy Kid series, Partypooper, really takes the cake! Expect gobs of fun and over-the-top antics as Greg throws an epic birthday party for none other than himself. So come celebrate and laugh alongside Greg, his family, and the entire world of Wimpy Kid fans.

Plot

According to Jeff Kinney in an interview, the main story of the book is that on the day of Greg's birthday, it's really quiet in the Heffley home, so he's bracing himself for a surprise party, but the surprise is that his family has actually forgotten his birthday. So the story goes viral on social media. His parents are getting Facebook-shamed, and Greg being Greg, he decides to leverage his parents' guilt and gets them to throw him a blowout birthday party and his goal is to absolutely maximize the presents.

Greg Heffley’s special day is right around the corner. It’s been real quiet and hoping his parents had planned him a surprise birthday party, but the real surprise is that they forgot his birthday. As soon as the word spreads, his family try to make up his birthday, but obstacles get in the way, a funeral, a wedding, and so much more. Will Greg enjoy his birthday, or will he just be the partypooper?

• According to the plot hint, it may be revealed that Uncle Gary might get married a 5th time.
• Also according to the plot hint, somebody will pass away in the events of “Partypooper”. This will be the third book that has a funeral involved, the first being The Long Haul and the second being Wrecking Ball.

Trivia

• This book is:
  • The first to have pink as the primary color on the cover.
  • The first to have the word "Diary" in different colors.
  • The first to have only 1 word as the title.
  • The first to have the subtitle of "300 million books sold".
  • The first to have the "of a Wimpy Kid" text made of something instead of being written, for this instance it being made of icing.
  • The second to have one of the letters being made out of something else (the "I" in "Diary" is a candle). The first was Hard Luck.
  • The second to feature Greg's birthday. The first was Dog Days.
  • The sixth book to be released in the 2020s. The fifth time is Hot Mess, the fourth is No Brainer, the third is Diper Overlode, the second is Big Shot, the first is The Deep End.
• There will likely be a gag about Greg only inviting his wealthier friends and family so he can get more quality gifts. This has been stated by Jeff as one of his ideas for Partypooper in an interview.
• This is the third time Manny has made an appearance on the book cover.
• This is the second time the cover has been centered around food, the first being Hot Mess. Ironically, Hot Mess is the book before Partypooper in the series.
• A hint towards the book's title was previously given on social media, being "___t___o___". Many fans correctly predicted the title to be Partypooper.
• It's possible that a prototype version of the cover could have shown Greg with a party popper in his mouth, due to the similarities between the face of Greg in the teaser image and the official cover.

Gallery

See Diary of a Wimpy Kid: Partypooper/Gallery