The mystery of what Penny's last name is on The Big Bang Theory has remained even after the show ended. However, as it turns out, the series had already secretly revealed it very early on. As the only female character from the original sitcom, Kaley Cuoco's Penny appeared in all 12 seasons of the CBS popular show. Although she seemed to stand out from her nerdy group of friends, she went through tremendous personal growth throughout those years, becoming one of the most popular characters in the series.

After moving to California as an aspiring actress, Penny eventually gave up on her Hollywood dreams. When season 8 started, she became a pharmaceutical sales representative working with Bernadette (Melissa Rauch). Despite her initial hesitation, she gradually rose through the ranks and appears to be perfectly content by the end of The Big Bang Theory. After all, both her personal and professional lives turned out great. While the show gave her a mostly satisfying ending with the revelation that she was expecting with Leonard, there is one mystery that the sitcom never outwardly resolved: the question of her last name.

Penny’s Last Name Was Revealed In The Big Bang Theory Season 2

A Package Delivery Revealed 'Teller' As Penny's Last Name

Penny's last name has been a pressing The Big Bang Theory query for years, and many expected that the finale would finally answer it. Unfortunately, despite the clamor for the detail, the showrunners decided to keep it a secret and maintain public curiosity even after the sitcom bowed out. Aside from this, they may have also come to this decision because they had already revealed the information during the very early years of the show.

As spotted by u/Quell_Alma on Reddit, in The Big Bang Theory season 2, episode 18, "The Work Song Nanocluster," Penny's last name was Teller before she became a Hofstadter. In the episode, Penny Teller started a new business making flower barrettes and called it "Penny Blossoms." At one point in the Big Bang Theory episode, Sheldon delivered a package of her materials, and in an easy-to-miss moment, her full name was shown printed on the box.

How Penny's Hidden Surname Is Linked To The Big Bang Theory's Creation

Penny's Name Dates Back To The Show's Original Pilot

The significance behind her last name remained uncertain, but Penny Teller's first name was decided even before the pilot for The Big Bang Theory was retooled to add Howard and Raj, with the show's planned title being Lenny, Penny, and Kenny. The producers, however, decided to change "Kenny" to "Sheldon" to pay homage to one of the most prolific TV producers — the late Sheldon Leonard who was behind a string of hit series, most notably The Dick Van Dyke Show.

Considering how Penny Teller sounds, it may have been a reference to American magicians Penn & Teller. Interestingly, Teller appeared in The Big Bang Theory playing Amy's father in the final season of the show, and Penny pointed out how the Fowlers' dynamic was similar to her and Leonard's.

Was Penny's Last Name Reveal In The Big Bang Theory Season 2 Intentional?

Did The Showrunners Intend For The Name To Be Such A Mystery?

While Penny Hofstadter was revealed to be Penny Teller in The Big Bang Theory season 2, fans wondered if this was intentional. Such a huge TBBT mystery was created surrounding Penny's surname that it's surprising producers would let that season 2 reveal go unchecked. Regardless, Penny's last name changed from "Teller" to "Hofstadter" towards the end of the series when she and Leonard got married.

What's curious with this incredible spot is whether The Big Bang Theory producers even including this detail back in season 2 (and forgetting the name would be on-brand given that Penny seemed to forget her own dad's name in TBBT's early seasons). At that point, though, the show was still starting to find its groove and build its fanbase. When asked repeatedly, people involved in the show either claimed that Penny's last name was a secret or that they didn't have anything set in stone.

Kaley Cuoco And TBBT Producers Have Said The Season 2 Reveal Is False

The Show's Propmaster Was Responsible For The False Reveal

Thanks to the publishing of The Big Bang Theory: The Definitive, Inside Story of the Epic Hit Series by Jessica Radloff, fans now know that Penny’s last name is not Teller, despite the shot of the package in the show. The book combines interviews with the cast and crew with stories from the set to give fans more information than they may have had about the show in the past. Some of that information directly addresses Penny’s last name on The Big Bang Theory.

According to executive producer Steve Molaro, the props team simply needed to put a name on the package in order for the label to look like a standard shipping label. It couldn’t be left with just Penny’s first name, or it wouldn’t appear like a real label. Molaro went on to explain, “We didn’t sanction it, we didn’t write it, and we didn’t intentionally put it in there.” He stressed that the name wasn’t canon and that the team behind the show had decided to never reveal her surname. In fact, they didn’t even have a last name in mind for Penny.

Propmaster Scott London revealed in the book that Bill Prady, co-creator of the series, offered up the name Teller for the label, but that it didn’t have a specific meaning for the show, and in fact, they never thought fans would be able to see the words on the label on camera. London had even previously used his own last name as a placeholder in early designs for props.

According to series star Jim Parsons, Penny’s last name was London in early scenes that included her mail. Parsons said, “We all found it amusing in a charming way that the propmaster had given her his last name.” Fans who truly want to know Penny’s last name in The Big Bang Theory might be disappointed that there isn’t one in canon.

A Penny Spinoff Could Reveal Even More About Her

Could Penny Return In A New Series?

While The Big Bang Theory ended in 2019, the success of the show has led to the franchise growing in the years since. The first new installment was the popular prequel series Young Sheldon, which explored the younger years of genius Sheldon Cooper. That series was popular enough to earn its own spinoff with Georgie and Mandy's First Marriage focusing on Sheldon's older brother and his first wife, Mandy, who plays a major role in Young Sheldon.

The Big Bang Theory's Spinoffs

Now comes word that there will be another spinoff with some of the ing characters from the original series stepping into the spotlight. Kibbler (Brian Posehn), Denise (Lauren Lapkus), and Stuart (Kevin Sussman) will return for an unnamed series. With all these plans in the works, it seems unlikely that the idea of a spinoff featuring Penny has not been considered.

There are a lot of directions the series could take, including offering a prequel series similar to Young Sheldon that looks at Penny's life before The Big Bang Theory and perhaps getting into the early days of her pursuit of acting. There is also the possibility of a sequel series that examines Penny and Leonard's life as parents. These characters are so beloved and have had a complicated romantic history that it would be interesting to see them in this new phase of their lives.

As with Young Sheldon, part of the fun of seeing these characters return in a new story is that it can fill in some of the blanks from The Big Bang Theory. If Penny were to return in any continuation of her character, it would be great to see the spinoff series definitively give an answer to her surname, a mystery that fans have been wondering about for years.