10 Best Penny Episodes Of The Big Bang Theory, Ranked

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Real ones know that Penny is the best character on "The Big Bang Theory." On the wildly popular CBS sitcom created by Chuck Lorre and Bill Prady that ran for twelve seasons and the same number of years, Kaley Cuoco plays Penny, a character who isn't initially given a last name — and who moves in across the hall from nerdy physicists Sheldon Cooper and Leonard Hofstadter (Jim Parsons and Johnny Galecki) in the show's pilot. As Penny — an aspiring actress from Nebraska — cautiously makes friends with the socially awkward Sheldon and Leonard, she meets their buddies and California Institute of Technology co-workers Howard Wolowitz and Raj Koothrappali, portrayed by Simon Helberg and Kunal Nayyar ... and eventually, the gang of five settles into a nice rhythm. (Amazingly, Cuoco wasn't the original Penny, but took on the character after test audiences didn't like Amanda Walsh's first female lead Katie. The rest, as they say, is history.)

Thankfully, at the end of Season 3, two female cohorts for Penny are introduced: Melissa Rauch's microbiologist Bernadette Rostenkowski-Wolowitz, who ultimately marries and starts a family with Howard, and Mayim Bialik's neuroscientist Amy Farrah Fowler, who starts a relationship with Sheldon. All of this is to say, though, that Penny, despite not being as book-smart as her counterparts, is sweet, socially brilliant, and a sort of audience surrogate who helps us better understand these sometimes bizarre scientists. So which are Penny's very best hours on "The Big Bang Theory?"

Considering that the show spans hundreds of episodes, it was tough to parse through all of them to find Penny's best outings, but that's our job here at Looper. Without further ado, here are Penny's 10 best episodes of "The Big Bang Theory," ranked.

The funny thing about the Season 3 episode "The Precious Fragmentation" is that Penny is not the center of the action, but it deserves a place on this list because it's the episode where Penny hauls off and deservedly punches Sheldon in the face. Allow us to explain. After the gang goes to a garage sale and returns to Sheldon and Leonard's shared apartment with a whole big box of junk, the guys find a golden ring that appears to be one of the "One Rings" made for Peter Jackson's universally beloved "Lord of the Rings" trilogy. Just like the ring in Jackson's movie, this piece of jewelry entrances and enchants the guys, all of whom want to keep it for themselves ... so at some point in the episode, it's given to Penny, who's mostly just miffed that it's the first piece of jewelry that her now-boyfriend Leonard has ever "given" her.

Penny and Leonard go to sleep in his room with the ring around Penny's neck, and when Sheldon sneaks in and tries to steal the ring off of Penny's neck, she does what anyone would probably do in that situation: she punches him. (When Leonard fully wakes up and Penny tells him what happened, he proudly says, "That's my girl.") Later, Penny gets Leonard to drop out of this incredibly stupid "competition," such as it is, by pointedly bringing a bag home from Victoria's Secret to lure him into her apartment, proving she's quite a bit savvier than any of these guys.

A lot of Penny's best episodes, weirdly, involve her unlikely friendship with Sheldon Cooper. Here's the thing about Sheldon Cooper: he's obviously heightened because he's a fictional television character, but he can also be a huge jerk, and Penny, who doesn't have a bachelor's degree and isn't a scientist, is one of his favorite targets. Still, in "The Adhesive Duck Deficiency," a standout episode from Season 3, Sheldon lends help to Penny — albeit quite begrudgingly — which ultimately deepens their bond.

While Leonard, Raj, and Howard are away camping to try and see the Leonid Meteor Shower, Sheldon is the only member of the gang around when Penny slips in the shower and dislocates her shoulder. Despite being predictably annoying about it, after finding Penny in her shower, Sheldon corrects her about her injury (clarifying the dislocated shoulder part by saying, "assuming you're correct that your right humerus is no longer seated in the glenoid socket, I would certainly think so" when she asks to go to the hospital and telling her that she only fell because she has "no safety mat or adhesive stickers to allow for purchase on a surface with a low coefficient of static friction") but takes her to the emergency room anyway. Penny on pain medication also makes this episode worth your while, but the bottom line is that Sheldon and Penny's friendship becomes the backbone of the show thanks to episodes like this.

Even though she's trying to pursue a career as an actress, Penny has a lot of career-related gambits on "The Big Bang Theory" — she works at the Cheesecake Factory for her day job, but she's always trying to find new ways to make a quick buck. In the Season 2 standout episode "The Work Song Nanocluster," she decides to start a line of floral hair and fashion ornaments that she dubs "Penny Blossoms," and naturally, she gets all of the guys to help her out. Before long, the situation just becomes a straight-up factory line, especially as Penny's orders spiral completely out of control and the gang can't possibly make enough Penny Blossoms to satisfy demand.

While Sheldon and Penny sing "Blow The Man Down" and handmake all of these Penny Blossoms, the other three guys eventually get involved too, but the reason that they end up totally overwhelmed is that Leonard gets the bright idea to add a "one-day rush" button on the Penny Blossoms website, completely overloading them with work. They all give up when, after finishing a whopping one thousand Penny Blossoms, they get an order for another thousand, and Penny never returns to this "job," such as it is ... but it's a pretty fun time while it lasts.

The penultimate episode of "The Big Bang Theory," Season 12's "The Change Constant," finds Sheldon enduring a ton of personal and mental strife over the mere concept of anything in his entire life changing in any sort of way ... and it also solves the running mystery of the building's elevator, which doesn't function for the entirety of the series up until this point. As Sheldon and Amy learn that they've been officially named the dual winners of the Nobel Prize in Physics for their shared work in super-asymmetry, Amy decides to get a makeover with Raj's help to prepare for the ceremony, and her haircut sense Sheldon into a spiral. Then, Penny gets home from work — at this point in the series, she has a thriving career as a pharmaceutical marketing representative — and shows Sheldon the functional elevator, and he absolutely loses it. Still, the two best friends decide to ride the elevator together, with Penny resting her head on Sheldon's shoulder.

In Jessica Radloff's 2022 oral history "The Big Bang Theory: The Definitive, Inside Story of the Epic Hit Series," Kaley Cuoco said that realizing she was the one who got to take the inaugural elevator ride was an absolute thrill ... and the live audience agreed. "When I found out I got to be in the elevator, that was it for me. I was so excited. I could not wait to do it in front of the audience," she recalled. "In front of our producer run-through, it killed! People were screaming for all the reasons that you would." With that in mind, it's easy to see why this is such an important Penny episode.

A lot of Penny's best and funniest episodes happen during the show's second season, and "The Barbarian Sublimation" is no exception. Penny is driving Sheldon absolutely insane in this Season 2 episode because she's not booking any roles, doesn't have any romantic prospects on the horizon, and wants to hang out at the boys' apartment all the time ... which makes Sheldon go so insane that he decides to get her completely addicted to a video game called "Age of Conan" (which is, incidentally, a completely real video game). With Sheldon's encouragement, Penny creates a character that she creatively names "Queen Penelope," and before long, she's completely addicted to the game to the point where she breaks into Sheldon's room in the middle of the night for gaming advice.

The iconic image of Penny with her hair piled on her head, food on her face, and bags under her eyes from "The Barbarian Sublimation" became a meme after this episode aired for a reason, and frankly, it's one of Kaley Cuoco's very best outings as an actress. Thankfully, Penny never plays "Age of Conan" again ... and subsequently, she never has to be in this frankly putrid state ever again on "The Big Bang Theory."

In Season 6 of "The Big Bang Theory," Penny and Leonard are back together after a few tries ... but when Leonard gets jealous over a community college classmate of Penny's, it seems like trouble in paradise. While trying to reassure Leonard that she's not interested in this other guy, Penny gets frustrated and tells him, "You're the one I'm with. You know I love you. So would you please relax, because you're driving me crazy!" When Leonard points out that Penny's never said "I love you" before, she's shocked to the point of tears ... but she means it.

In Jessica Radloff's book, Kaley Cuoco said that she knew this moment would happen on "The Big Bang Theory," but that she didn't know precisely when it would come ... and she was absolutely thrilled with the result once it actually came to pass. "Weeks later, when we saw the script and did a table read, I thought, 'Oh my God,' it was such a well-written scene," she recalled before revealing something astonishing: "Then, on the shoot night, we actually did that in one take." Not only that, but Cuoco's emotion was real:

"I cried at the table read. I cried in the rehearsal. I cried in run-throughs. That's why I had to take such a long beat, because I thought, 'If I close my eyes, tears are just going to come streaming down my face,' and I wanted it to look more pent-up. I thought, 'Oh, they'll tighten that [in editing],' but they left it all in there. I guess they liked it."

Honestly, Cuoco's assessment is fair ... because if you're invested in Penny and Leonard's relationship by the time you get to "The 43 Peculiarity," you'll cry too.

Okay, so "The Pancake Batter Anomaly" does, on the surface, seem like a Sheldon-centric episode because it's entirely about Sheldon getting sick and all of his friends running for the hills as a result. Leonard knows better than to deal with Sheldon when he's sick, because he gets so needy — to be completely fair, Leonard knows better than anybody that Sheldon does things like request urine tests when he's sick to be sure that his kidneys aren't shutting down — which leaves Penny as the only person to help. She does, and in the process, she learns the song "Soft Kitty," which Sheldon's mother used to sing to him whenever he didn't feel well. 

In Jessica Radloff's oral history, casting director Ken Miller, who worked extensively on the show, said that this episode helped cement the friendship between Sheldon and Penny in a real way. "The chemistry became so impactful between those two characters," Miller shared. "The writers saw it helped soften Sheldon's edges even more by allowing Penny to be the one person that really got him."

As far as writer and executive producer Steve Holland is concerned, he also loves this pairing. "We found out early on that Sheldon and Penny were a powerhouse combination. There was something very funny and sweet about that relationship," he mused. "I think some of our best scenes were those two. They were so opposite, and they frustrated each other, but there was this deep, deep love." This is a perfect way to describe Penny and Sheldon's relationship, and honestly, "The Pancake Batter Anomaly" is a huge part of their story. Plus, even though the two bond even more in Season 1, this is the real start of their friendship.

In the Season 11 episode "The Solo Oscillation," Sheldon decides he wants to do his important scientific work on his own ... and when he kicks Leonard out of the apartment, he ends up faced with a bored, restless Penny, who orders a pizza and enjoys it on the couch. (For context, the central apartment in the show now belongs to Penny and Leonard, who are married; Sheldon and Amy live in their own place now.) As Sheldon waxes poetic about complicated subjects like dark matter and string theory, Penny muses about the cheese stuffed into the crust of her pizza, and Sheldon, weirdly, takes notice.

What happens from that point on is that Penny accidentally learns what string theory is without really knowing it — when she describes it as vibrating guitar strings, even Sheldon is struck by how "correct" that view of the theory is — and together, they end up chatting until Sheldon makes a breakthrough in his own work. Probably, the funniest part of the episode is when Sheldon proudly tells a surprised Leonard and Amy that Penny "solved" all the mysteries of string theory, but still, this is a great Penny episode, proving that she's incredibly intelligent even without having a PhD ... and proving that her bond with Sheldon is truly unbreakable at this particular point in "The Big Bang Theory."

Fans of "The Big Bang Theory" know that Sheldon is difficult, to put it lightly ... and in the Season 2 episode "The Bath Gift Item Hypothesis," he has the gall to get mad at Penny for giving him a Christmas present. After Penny tells Sheldon and Leonard that she'll leave their gifts under the tree, Sheldon is appalled, claiming she hasn't given him a present but an "obligation," and sets out to find something to give her in return. Sheldon, predictably, concocts a genuinely absurd plan. After buying multiple sizes of gift baskets filled with luxury bath items — all at different price points — Sheldon tells Leonard that he'll try and figure out what Penny spent on his gift, excuse himself, and bring her the "correct" gift basket in return.

Sheldon's plan, however, is completely derailed when Penny brings him an unexpectedly perfect present. Fresh off a shift at the Cheesecake Factory, Penny brings Sheldon what appears to be a simple used napkin at first, only to reveal that the napkin was used and signed by Leonard Nimoy, best known as Spock on "Star Trek." Sheldon nearly faints when he reads the signature that instructs him to "live long and prosper" and is frankly a little too excited that he now has some of Nimoy's DNA ... and he lets Penny keep all of the baskets. 

As Kaley Cuoco told Entertainment Weekly in 2012, she loves this episode. "My favorite episode will always be the Christmas episode when Penny gives Sheldon a napkin signed by Leonard Nimoy," she shared. "Sheldon is so overwhelmed with emotion he proceeds to hug Penny for the first time ever! I think Jim and I had our own set of secret tears flowing."

Penny admittedly has a lot of great episodes on "The Big Bang Theory," but none come close to Season 9's standout "The Celebration Experimentation." When Amy announces that she wants to throw a surprise birthday party for her boyfriend Sheldon, she forges ahead despite both Penny and Leonard telling her that it's a terrible idea ... and when Sheldon walks into his apartment and sees his best friends flanked by pop culture icons like Wil Wheaton and even "Batman" star Adam West — who calls him Sherman — he freaks out.

Part of this is because Sheldon hates surprises, and part of it is because his sister once pranked him by claiming Batman would show up at his birthday party ... but either way, the damage is done and he flees into the bathroom. Leonard and Amy argue about who should go and get him, but in the end, it's Penny. After he hesitantly lets her in — asking how she's sure he's not actively on the toilet only for her to respond "because you email me your bathroom schedule once a week, even though I've clicked unsubscribe, like, a thousand times" — the two sit on the edge of the bathtub, and Penny shares that she feels bad that she was once a bully like Sheldon's sister. As she says:

"My point is, there was a time I never would've been friends with someone like you, and now... you are one of my favorite people. So, if what you need is to spend your birthday in a bathroom, I'm happy to do it with you."

This is Penny and Sheldon's best episode, but it's also Penny's best — showing how much she's grown over the course of the series. "The Big Bang Theory" is streaming on HBO Max now.