For 12 seasons, The Big Bang Theory told us almost everything about Penny — except her last name. Even after marrying Leonard and becoming Hofstadter, her original surname was never disclosed. This wasn’t an accident: Penny herself was a reworked version of an earlier character in the show’s initial pitch, and the writers ultimately chose to keep that detail a mystery.
Penny may be one of The Big Bang Theory’s most beloved characters, but her last name before marriage was never revealed. While she eventually became Penny Hofstadter, fans were left guessing about her maiden name. The reason traces back to the show’s early development, where Penny evolved from a different character — and the writers decided the mystery was worth keeping.