Meek high school student Jerry Mitchell and sister Brei are home alone while their parents vacation.

Buddy, who has a touch phobia, throws Jerry against a wall and declares the pair will fight outside school at 3:00 P.M.

The clock finally reaches the appointed hour, and the fight begins before hundreds of eager students.

Buddy takes out his brass knuckles, but Vincent distracts him and he drops the weapon, which Brei picks up and slips to Jerry.

Weaver is filled with new gossip, as Jerry, now allegedly dating his crush Karen, replaces Buddy as hot topic.

[3] Roger Ebert of The Chicago Sun-Times gave the film one out of four stars, declaring the plot to be "pretty stupid" and lamenting that the bully Buddy Revell, "the most interesting character", was underdeveloped.

[4] In a retrospective review from 2016, critic Rob Hunter called the film "a wildly inventive and energetic look at the failures and successes of a typical high school day, and it shapes the daydreams and anxieties into an exaggerated delight".

[6] In 2017, Adrian Halen wrote that Three O'Clock High was released in "an era when The Breakfast Club, Pretty in Pink, Ferris Bueller's Day Off, National Lampoon’s Vacation and Weird Science were the general norm for moviegoers".