Updated: June 03, 2023

Theodore "The Beaver" Cleaver is the fictional title character in the American television series Leave it to Beaver. Originally played by Jerry Mathers, seven year old ( "almost eight" ) Beaver is son to June and Ward Cleaver ( Barbara Billingsley and Hugh Beaumont ) and sibling to thirteen year old Wally Cleaver ( Tony Dow ).

Beaver prefers "messin' around" with his pals and reading comic books to attending church or taking dance lessons. Most episodes in the series feature Beaver getting into some sort of trouble at home, in school, or around the neighborhood and then receiving timely and appropriate moral instruction from his father regarding his misbehavior.

Leave it to Beaver was created by writers Joe Connelly and Bob Mosher, who found inspiration for dialogue and plot lines among their own children. Beaver was based on Connelly's son Ricky.

Theodore "Beaver" Cleaver is portrayed by Jerry Mathers in the pilot "It's a Small World", the original series, the spinoff telemovie, Still the Beaver and the sequel series, The New Leave it to Beaver. In the reunion telemovie and the sequel series, Beaver is a divorced father of two children living at home with his widowed mother, June. In the 1997 feature film adaptation of the original series Leave it to Beaver, Beaver is played by Cameron Finley