Clarence "Lumpy" Rutherford is a fictional character in the television sitcom Leave It to Beaver.

In the third-season episode "Wally's Test," Lumpy's first name is spelled Clarance, not Clarence.

A running gag on the show was to have Fred, who always referred to his son as Clarence, call him "Lumpy" when angry.

Lumpy's mother Gwendolyn ("Geraldine", in some early episodes) and his younger sister, Violet (who is about Beaver's age), round out the family.

In another episode, Wally and Eddie Haskell play a prank on Lumpy that involves the rear axle of his car being removed with a chain.

Lumpy and Beaver form a successful business partnership (the "Cleaver and Rutherford Co.").