Leave It to Beaver (1957–1963)
Frequently Asked Questions
In its first season, CBS. It moved to ABC for its second season and remained there for the rest of the series.
It isn't explained until the final episode of the series. He is called this because when Beaver was a baby and Wally was also very young, Wally could not pronounce "Theodore" correctly, and it came out sounded like "Beaver." So the nickname stuck.