Mr. Louie is Screwy is the twentieth book in the My Weird School series.
When the hippie crossing guard, Mr. Louie, puts a love potion in the water fountain before Valentine's Day, everyone in Ella Mentry Elementary School falls in love.
The book begins with AJ, Ryan, and Michael explaining to each other about how they hate school more than anything. The school crossing guard, Mr. Louie, overhears the conversation and tells them that there's too much hatred in the world. He tells them that he is obsessed with love and drinks a love potion every day. AJ suspects that Mr. Louie is probably just kidding. Mr. Louie tells AJ that if he doesn't say that he loves school, Mr. Louie will tell the whole school that AJ is secretly in love with Andrea.
- Miss Daisy and Mr. Macky get married in this book.