“Friends” is about the core group of buddies that the beloved sitcom is named after: Ross (David Schwimmer), Rachel (Jennifer Aniston), Monica (Courteney Cox), Chandler (Matthew Perry), Joey (Matt LeBlanc), and Phoebe (Lisa Kudrow). They’re the central focus of the show and their relationships with each other are the most important dynamics that are explored throughout the series. However, it’s often secondary characters that become fan favorites in the world of TV, and “Friends” certainly has a lot of memorable ones.

We’ve taken a good look at every side character who appeared in four or more episodes of “Friends” and pulled out those whose arcs were most critical to the main gang. We narrowed it down to characters who appeared across multiple seasons of the show and who added some value to proceedings, be it through comic relief or by shaping the arcs of our six leads. For our final order, we assessed their performance in these key areas and then ranked them from worst to best. This list is for all the “Friends” fans out there who feel like the secondary characters sometimes steal the show.

Played by Eddie Cahill with a significant arc in Season 7, Tag is the assistant that Rachel hires after getting a promotion at Ralph Lauren. It makes for uncomfortable viewing these days, given that Rachel hires him because he’s attractive and soon after begins secretly dating him. It isn’t quite as horrible a power dynamic as Ross has with the 20-year-old student he dates in Season 6, but it’s still pretty bad. Cahill is not a particularly gifted comedic actor and Rachel’s relationship with Tag feels almost like a regression for her character. Overall, he seems like a placeholder, something for Rachel to focus on while the show gives the spotlight to Monica and Chandler as they plan their wedding.

Ross is still reeling from his breakup with Rachel when he meets Emily (Helen Baxendale) and he needs something to distract him from the heartbreak of ending a serious relationship. As for Emily, she’s the English niece of Rachel’s boss at Bloomingdale’s and the perfect person for Ross to move on with. However, Emily herself is a very under-developed character. Baxendale isn’t a bad performer, but she has few opportunities to shine. Emily causes Ross a lot more misery than joy overall. That said, she’s involved in some of the best ever “Friends” episodes, including “The One with All the Rugby,” “The One with the Fake Party,” and the explosive “The One with Ross’s Wedding,” one of the most gasp-worthy sitcom finales in the history of television.

Monica and Rachel’s downstairs neighbor, Mr. Heckles (Larry Hankin), isn’t in many episodes of “Friends,” but he makes quite an impression in those first few seasons. From kidnapping Marcel to pretending to be Chandler’s new roommate (a little maneuver that viewers get to enjoy during a flashback episode in Season 3), Heckles wrought some pretty hilarious hell on the “Friends” gang when he was around. Hankin has some great lines on the show and, much like Ugly Naked Guy, provides a rich running joke for the characters and viewers alike. “The One Where Heckles Dies” is a great episode for Chandler in terms of character growth, but it’s a shame to lose Heckles so early in the show.

The first time we see Dr. Green (played by the late Ron Leibman, one of the many “Friends” actors who have sadly passed away) on screen is at Rachel’s birthday party in Season 2, where the gang must run two parties (one in Joey and Chandler’s apartment and one in Monica and Rachel’s) in order to prevent a run-in between Dr. Green and Rachel’s mother (his soon-to-be ex-wife). Dr. Green provides a great comedic foil to Ross, a pattern that repeats itself throughout the series. While Rachel’s father isn’t the best side character on the show, he definitely fits well into Rachel’s life and the comedic stylings of the sitcom overall. He mostly serves as a factor in Ross and Rachel’s relationship, but one of his funniest episodes is actually “The One with the Stripper,” where Rachel takes Phoebe to a dinner with her father so that she can tell him she’s pregnant.

Carol (who was played by Anita Barone in the pilot and then Jane Sibbett for the rest of the show) is part of one of the most interesting plot lines on “Friends.” The fact that a sitcom that started in the 1990s initially centered on such a complicated dynamic as the one Ross has with Carol and Susan (Jessica Hecht) is very interesting. Ross is forced to come to terms with Carol’s sexuality and her pregnancy almost immediately following their divorce, and it’s a truly complex situation that gives us some of the most emotionally satisfying moments of the show. 

Unfortunately, while she’s involved in some great moments, Carol herself isn’t a particularly interesting or funny character. There are times in the show where Carol serves as a source of emotional support to Ross (for example, she is reluctantly compelled to take care of him when his friends go away the weekend after his breakup with Rachel in Season 3), but she almost never talks about herself or reacts to him or any of the main characters in a way that shows her personality, unlike her partner, Susan, who is an important foil for Ross throughout the show.

Estelle (June Gable) is another classic recurring character from “Friends.” A talent agent that recruits Joey in Season 1, Estelle remains a regular figure in Joey’s stories for all ten seasons of the show. Her timing is fabulous and she always provides an extra bit of comedy in the moments where Joey’s story requires some industry exposition. Estelle is exactly the kind of agent you’d expect an actor like Joey to have; mostly incompetent but still a little scrappy. Really the only reason she’s lower on this list is because she sells four of Joey’s six tickets to his own film premiere! One of the stars of the movie literally can’t bring his friends to his own premiere because his agent scalps them. It’s very uncool — but very Estelle.

Charlie, played by Aisha Tyler, is one of a disappointingly small number of named POC characters on the show throughout its ten-season run. She’s a beautiful, intelligent paleontology professor and becomes an immediate love interest for both Ross and Joey. Charlie is certainly a catalyst in moving forward a lot of interpersonal development between several of the gang, and Tyler always gives a charming performance on screen. That said, it’s hard not to resent Charlie a little bit when her presence is definitely a big part of what facilitates Rachel and Joey’s failed romance, one of the most hated “Friends” storylines.

One darker gag that carries through most of the show is Monica’s troubled relationship with her mother, Judy Geller (Christina Pickles). No matter what Monica does, Judy is always disappointed in her, despite being constantly impressed by Ross. Judy’s treatment of Monica gives viewers an insight into why Monica is such a perfectionist. One of Judy’s funniest moments comes in “The One with the Sonogram at the End.”

In this Season 1 episode, Judy and her husband Jack are visiting Monica and Ross for dinner in the city and Monica has been begging Ross to confess the end of his marriage and Carol’s pregnancy to their parents all night. Ross does, hoping to relieve some of the scrutiny being levied against Monica for her various mistakes (which, to any rational person, would be nothing compared to Ross’s situation). When Ross finally confesses, the Gellers sit in shock for a few seconds before Judy turns to Monica and says, “And you knew about this?!”

Even though Dr. Richard Burke (Tom Selleck) and Monica break off their romantic relationship for good (well, mostly) at the end of Season 2, he continues to loom large in her story for years to come and makes several reappearances on the show. How could he not remain a fixture? Not only is he the first person that Monica seems to really fall for in her life, but his relation to her is messy: Richard is Monica’s parents’ best friend and Monica is so much younger than him that she graduated high school with his daughter!

Even better than the drama Richard brings to the show is how fun a character he is to watch. Richard’s ability to provide a straight man for Monica makes him essential to her character growth. Add in the fact that he’s played by Tom Selleck, a man who could probably go on TV reading the phone book and still leave viewers charmed, and Richard is easily one of the best secondary characters in “Friends” history.

Hank Azaria’s David, aka David the Scientist Guy, is an almost mythical figure in “Friends.” Phoebe’s one-that-got-away doesn’t appear in many episodes, but he feels ubiquitous and essential to Phoebe’s romantic journey. Even though she and David only connect briefly in a single Season 1 episode before he leaves to do scientific research in Minsk, their relationship is very important to Phoebe. David is Phoebe’s “what if” scenario for years and is most likely a big part of the reason that Phoebe struggles to commit to any serious relationships throughout the series. Hank Azaria is as funny as ever as the bumbling physicist, and while he is not Phoebe’s endgame, it’s satisfying that their relationship resolves before the end of the show when Phoebe ultimately chooses to be with Mike (Paul Rudd).

At first, Susan (Jessica Hecht) is the kind of character who’s easy to hate. After all, Ross is one of the main characters of “Friends” and he hates her, viewing her as the reason Carol left him. Once audiences get a better understanding of Ross and his flaws, though, the situation becomes more nuanced. Over time, viewers begin to understand Susan, and so does Ross. She contributes to his character arc in subtle but memorable ways: In “The One with the Lesbian Wedding,” the moment when Susan asks Ross to dance following her and Carol’s nuptials is one of the most emotionally earned in the entire show. Susan sees and appreciates what Ross does to see Carol happy, and if there’s one thing they always agree on, it’s that they’ll do almost anything to keep Carol (and Ben) happy.

Central Perk manager Gunther, played by the late James Michael Tyler, is the closest thing there is to a “Friends” main character that isn’t Ross, Rachel, Monica, Joey, Chandler, or Phoebe. He’s by far the most prevalent secondary character by number of appearances, and even though many of these are so minor that he’s basically an extra, Gunther’s bright blonde hair and colorful coffeehouse vests make him a visual focal point. As the show goes on, Gunther’s character lore grows to a point where he’s invited to the gang’s parties and even hires Joey as a Central Perk waiter.

Gunther’s infatuation with Rachel, and more specifically her complete obliviousness to said crush, provides a lot of jokes that often feel like a secret between the audience and the writers; even the friends themselves aren’t in on them. What’s great about Gunther is that he’s almost an audience proxy — whether he’s scoffing at Joey trying to convince a woman that he doesn’t normally go up to strangers and ask them out, or the only person brave enough to tell Phoebe’s shorts-wearing date to “put the mouse back in the house.”

Frank Jr. (Giovanni Ribisi) is, laugh for laugh, one of the funniest “Friends” characters, secondary or otherwise. Ribisi actually played a random guy in a Season 2 episode before making his debut as Frank (he’s the guy who accidentally tips Phoebe with a condom in “The One with the Baby on the Bus”), but fans of course know him best as Phoebe’s half-brother. Their reunion is both sad and joyful: Sad because Frank, like Phoebe, was abandoned by their father, and joyful because now he has a sister and she has a brother.

When Frank visits Phoebe in the city, it’s clear that he’s not the brightest bulb in the box. He’s obsessed with melting things and mistakes Phoebe’s massage parlor for the kind that serves as a front for sex work, just because it’s in Manhattan. Frank has such a good heart, though, and Ribisi’s comedic skills shine even more brightly when he returns to Phoebe’s apartment later in the series. Turns out he’s been pursuing a relationship with his much older home economics teacher, Alice Knight (Debra Jo Rupp), and it’s hilarious to see Phoebe — who is such an unconventional character — dealing with such an unconventional situation. 

Mike Hannigan is just as likable as Paul Rudd, the actor who plays him. Rudd has the ability to make a home for himself in basically any project he’s a part of, and as soon as his character answers Joey’s desperate call for “Mike!” in Central Perk, he becomes a delightful part of the show. Mike has an interesting backstory — he is a recently divorced lawyer who left his job to pursue his dream of becoming a professional pianist — and it creates a very believable and heartbreaking obstacle in his relationship with Phoebe. Rudd has a bunch of memorable moments on the show and actually does some great work opposite, not just Lisa Kudrow, but also David Schwimmer, Matt Leblanc, and Courteney Cox. He fits seamlessly into their group when he’s around and is a joy to watch.

If the six main characters in “Friends” were making this list, they’d probably put Janice (Maggie Wheeler) near the bottom. Janice’s biggest crime? She’s kind of annoying. Her laugh is a bit obnoxious and she reacts to every surprise with an over-the-top “Oh… My… God!” She is introduced in Season 1, Episode 5, “The One with the East German Laundry Detergent,” in which Chandler spends the entire episode attempting to break up with her. She and Chandler remain weirdly on-and-off for many seasons, with the latter spending most of that time regretting their relationship and Janice giving him infinite chances. Her best episode is definitely “The One with All the Rugby,” where Chandler — instead of once again telling Janice he’s not interested in her — pretends that he needs to move to Yemen for work.

Jack Geller (Elliott Gould) is the dad that makes everyone laugh, even when he’s not trying to be funny. As the father of Ross and Monica, Jack is often present for big moments in their lives in addition to those episodes that surround the Geller family dynamic itself. In “The One After Ross Says Rachel,” Jack’s line “Boy, bad time to say the wrong name, huh Ross?” became an instant classic, and his refusal to help Ross find Chandler in “The One with Monica and Chandler’s Wedding” when he thinks it’s for a game of hide and seek is even funnier.

However, while he’s one of the funniest secondary characters in all of “Friends,” some of Jack’s best moments are those where he’s actually a great father. He spends time in Season 1 reassuring Ross about the love he’ll have for his child when Carol gives birth, and it is his warm, familiar presence that finally allows Monica to rest peacefully following her breakup with Richard. He’s not a perfect father by any stretch of the imagination, but he’s there for his kids when they need him most.

It almost feels like cheating to name Ursula Buffay as the best secondary character in “Friends” given that she’s played by one of the main cast members (Lisa Kudrow), but she deserves the top spot. As only hardcore “Friends” fans know about Ursula, she’s actually a character that existed before Phoebe; she started as a side character (an erratic waiter) on another NBC show called “Mad About You.” Kudrow kept her role as Ursula on “Mad About You” after being cast on “Friends,” and the creators of “Friends” asked to do a crossover, deciding that Phoebe could actually be Ursula’s twin.

Kudrow is undoubtedly a great character actor and “Friends” wouldn’t have been the same without her, but she reportedly struggled when it came to filming the scenes in which Phoebe interacts with Ursula. She had her actual sister on set to act as her double, and this apparently threw her off her game. “I think feeling the [stress] she put her sister into by being the double was more in her head at the time, so those scenes were a little bit tricky to shoot,” executive producer Kevin S. Bright told Entertainment Weekly. “But it ended up being a lot of fun when you put it together.”

However, while Kudrow seemingly struggled with Ursula’s introduction, there’s no doubting that she became a hugely important part of Phoebe’s arc. Phoebe obviously needs to be likable enough to be a main character on a mainstream sitcom, but the writers were free to go anywhere with Ursula, and boy did they. How could anyone forget Ursula’s adult film “Buffay, the Vampire Layer,” or the fact that she sells Phoebe’s birth certificate to a Swedish runaway? She’s a chaos agent and entirely morally ambiguous, and that’s what makes her so memorable.