Diary of a Wimpy Kid: No Brainer

Diary of a Wimpy Kid: No Brainer is the 18th book in the Diary of a Wimpy Kid series written and illustrated by Jeff Kinney. It is a sequel to Diper Överlöde and the predecessor to the upcoming Diary of a Wimpy Kid: Hot Mess. The book was unveiled on May 17, 2023, with the hardcover releasing on October 24, 2023.

Plot
Greg gives his opinions on the human brain and says kids mostly use their brains when it comes to school. He also talks about how wild the kids at his school are and how he wishes they would stop fooling around and "get down to business" once school starts. He also talks about how most teachers at his school teach the class "stuff you can't even use."

After the middle school's test scores plummet to the point where it is featured on the news, the superintendent fires the current principal, Mrs. Mancy, and pulls the old principal Mr. Bottoms out of retirement. Mr. Bottoms makes a lot of changes to the school, such as cutting some classes and creating a club called the High Flyers Club which encourages the students to get better grades, resulting in more cheating on tests.

After a lunch lady, Ms. Podsner, introduces a fudge-covered tofu dog called the "fudgedog", the test scores plummet once again due to increased visits to the nurse's office, resulting in its discontinuation. It eventually makes a return but in a different style ("fudgedog fingers").

Mr. Bottoms comes up with ideas to raise money for the school. One of the ideas was to change the school's name to raise money. Slacksville bidded to change the name to "Slacksville Rules! Middle School" and even though the town was willing to pay the required price Mr. Bottoms refuses due to an ongoing dispute between the two towns. (See Big Shot). Eventually the company that used to the school's pest control bidded to change the name to "1-800 DED BUGS Middle School" which ends up becoming the school's name. Mr. Bottoms also starts up the Platinum High Flyers Club, which instead of having good grades all you have to do is to be willing to put down $12.99 per month. The new club also offers more perks like full size candy bars instead of "tiny bags of peanuts" They also receive a Platinum Pass which allows them to go whenever they want wherever they want; and with the donation of bathrobes and slippers, they don't even bother attending class anymore.

Later Greg's mother and father attend the annual PTA (parent-teacher association) Auction/Fundrasier and due to Greg's mom being the secutary in the PTA Greg gets roped into going. He works as a server for the night and during the live auction Greg's mom bids for the principal of the day, and depite Greg's dad hinting that she should stop she ends up winning, making greg the principal for the day. The next day Greg goes to school and finds out the principal is in a hurry to leave leaving Greg confused. Greg finds himself thrust into the duties of being principal and after finding out just how stressful being principal is, he decides to quit with a few hours still on the clock, leaving the school without a principal for the rest of the day.

After a while, the school's newspaper announces that the state is threatening to close the school if the students fail another standardized test in the following week and, if that happens, they will be sent to two schools in neighboring towns. Greg finds out he will be transferring to the better of the two schools, Fulson Tech, while his friend Rowley will be sent to the middle school in Slacksville, Greg's rival town. But after Alex Aruda, one of the smartest kids, is enrolled in a private school, the list flips, resulting in kids going to Slacksville when they were originally going to Fulson Tech and vice versa, causing Greg to panic. Greg's school performs poorly on the test due to the student going to Fulson Tech not even bothering to do well, and bees invading the classroom. The state refuses to give them a do-over, resulting in the school shutting down.

After finding that the quality of education in Slacksville's middle school is even lower than that of his former school, Greg gains popularity there for being able to tell the time and receives the nickname "Time Lord". After introducing fudgedogs to Slacksville's middle school (and simultaneously increasing his popularity in the process), Greg gets a girlfriend named Sophie during the first week and finds out that her grandfather is Larry Mack, the founder of Greg's former school. His son, Larry Mack Junior (who is Sophie's father) thinks of Greg as a bright kid because of the education he received at his old school, resulting in him reopening the school under the name Larry Mack Junior Middle School. The school's former students are called back from Slacksville and Fulson Tech, and Sophie breaks up with Greg (the former didn't want to date long-distance). A sentient cleaning robot seen earlier in the book is named the temporary principal, as Mr. Bottoms declined to return.

Reception
The book received generally positive reviews. Common Sense Media gave the book 3 out of 5 stars.

Sequel
A sequel, titled Diary of a Wimpy Kid: Hot Mess, was announced in January 2024 and will release on October 22nd of that year.