Partypooper is the 20th book in Jeff Kinney's global smash-hit Diary of a Wimpy Kid series, where Greg Heffley is planning the ultimate birthday party for himself. When the guest list grows, the decorations flop, and the surprises backfire, this birthday bash turns into a total blowout, just not the kind Greg had in mind.

Packed with cake disasters, family fiascos, and classic Wimpy Kid humor, this hardcover book features 224 pages of illustrated diary-style storytelling. Perfect for readers ages 8 to 12, this installment continues Greg's hilarious middle school misadventures with the signature cartoon illustrations and laugh-out-loud humor that has made the series a number one New York Times bestseller with over 300 million copies sold worldwide. Published by Amulet Books on October 21, 2025, this is the latest addition to the beloved series that has been adapted into Disney+ movies and won six Nickelodeon Kids' Choice Awards for Favorite Book.