For over a decade, The Big Bang Theory left one question unanswered: what is Penny’s last name? Despite being a central character, the sitcom never revealed her maiden name during its 12-season run.
Fans spotted various props suggesting surnames like “Teller,” “London,” and even “Penny,” but these were ultimately meaningless. The truth was officially confirmed in 2022 through The Big Bang Theory: The Definitive, Inside Story of the Epic Hit Series. Co-showrunner Steven Molaro clarified that Penny was never given a canonical last name—and never will be.
Kaley Cuoco admitted she occasionally considered creating one for the character but felt it was too strange after years of simply calling her “Penny.” In the end, the mystery wasn’t overlooked—it was intentional.