Summary

• It's Always Sunny in Philadelphia has become one of the longest-running sitcoms in TV history.
• The show has been renewed through season 18 and offers plenty of hilarious and wild stories.
• Across its 16 seasons so far, the sitcom has shown a lot of variety and some episodes have become instant classics.

Looking at the It’s Always Sunny In Philadelphia seasons ranked shows why the sitcom has become one of the longest-running in television history. Following a historic deal with FX, It's Always Sunny in Philadelphia was renewed through season 18. While there will be plenty of misadventures to come in the future with the gang at Paddy's Pub, the 16 seasons the show has already produced leave lots of hilarious fun for viewers, even if some seasons of It's Always Sunny in Philadelphia are better than others.

Though there will be a wait until It's Always Sunny in Philadelphia season 17, it remains one of the best shows to revisit and binge-watch, with each season offering a collection of wild, edgy, and smart stories with these wonderfully despicable characters. As with any show, there are times when It's Always Sunny seems to falter with the quality of its stories and other instances that show it has improved with age. As a result, It's Always Sunny in Philadelphia seasons show variety throughout the sitcom's historical run.

16 Season 1

Best Episode: Underage Drinking: A National Concern

The show premiered with a slew of extremely edgy material right out of the gate. In fact, season 1 likely remains the most controversial when compared to later seasons of It’s Always Sunny In Philadelphia, as seen in episodes such as "The Gang Gets Racist," "Charlie Wants an Abortion," "Charlie Has Cancer," and "Underage Drinking: A National Concern."

The season is hilarious, but with the absence of Danny DeVito - and being fairly grounded in reality compared to the later seasons – it doesn’t quite feel totally like the Always Sunny that audiences have come to love. Still, even with just seven episodes, the first season competes well with even the latest seasons. It does feature the lowest Rotten Tomatoes score and is the only season that ranks under 80% by critics. However, as a starting point, it really sets the table for what fans would get used to over the years.

15 Season 14

Best Episode: The Janitor Always Mops Twice

Out of every season of It’s Always Sunny In Philadelphia, few are as well-produced as season 14. "Thunder Gun 4: Maximum Cool" sees It's Always Sunny guest star Dolph Lundgren make an extended cameo in a fictional Hollywood action blockbuster, with Charlie hilariously failing to comprehend the extremely simple premise.

Meanwhile, "Waiting for Big Mo" is a great episode that is a tribute to the play Waiting for Godot, and includes a metacommentary about whether being in one of the most successful shows in history is still worth it — plus hilarious references to Wu-Tang Clan's "C.R.E.A.M." However, the crown jewel of the season may be “The Janitor Always Mops Twice,” which turns the show into a parody of 1940s noir movies. That look and its aesthetics show the series sits on a completely different level from other sitcoms.

14 Season 12

Best Episode: The Gang Goes To A Water Park

It's Always Sunny in Philadelphia season 12 is propped up by some episodes that became instant classics. “The Gang Goes To A Water Park” is one of the most hilariously grotesque episodes of television ever. Meanwhile, shot in the style of a crime documentary, "Making Dennis Reynolds a Murderer" greatly pays off the running joke about Dennis being a serial killer.

Most notably, episodes like "Cricket's Tale" and "The Gang Turns Black" underscore how the series pulls off using offensive elements for comedic social commentary. This season does a better job than many others when it comes to the series being more conscious of pointing out the character's bigotry and interactions when it comes to marginalization. "Hero or Hate Crime" is a great example of this done tight, and it was a perfect moment when Mac came out.

13 Season 15

Best Episode: The Gang Carries A Corpse Up a Mountain

What truly differentiates the 15th season from every season of It’s Always Sunny In Philadelphia is that it features the gang's return after the pandemic, which it quickly addresses in "2020: A Year In Review." The season then gets off to a running start with "The Gang Makes Lethal Weapon 7," keeping the attached controversies alive and even more hilarious.

After the gang journeys to Ireland to finally reveal Charlie's real father, culminating in the finale, "The Gang Carries a Corpse Up a Mountain," the series ends on a strangely hopeful note. This was a shorter season than others, but one of the best parts was the extended storyline (the first since Dee was pregnant in season 6).

With both Mac and Charlie seeking their sense of identity throughout the season, it offers up more storyline than just quick jokes and cringe-worthy moments. Colm Meaney was also great in his guest role this season.

12 Season 6

Best Episode: A Very Sunny Christmas

Compared to every season of It’s Always Sunny In Philadelphia, even the first, season 6 is known for being controversial. It opens with "Mac Fights Gay Marriage," in which Mac gets angered by finding out that a trans woman he dated is married to a man - consistent with Mac's then-story arc of being a closeted gay man.

Other notable episodes include "Charlie Kelly: King of the Rats" and "Dee Reynolds: Shaping America's Youth," the beginning of the gang's controversial "reboots" of Lethal Weapon. Meanwhile, “A Very Sunny Christmas” is one of the very best season finales in It's Always Sunny in Philadelphia.

The most notable thing about season 6 was that it was the first time the show attempted a season-long story arc. Most seasons' episodes were self-contained, but this season offered up Dee's pregnancy (which was done to work around Kaitlin Olson's pregnancy). "Who Got Dee Pregnant?" might be the best unreliable narrator episode in It’s Always Sunny In Philadelphia history, which is saying something.

11 Season 11

Best Episode: Mac & Dennis Move To The Suburbs

It's Always Sunny in Philadelphia got off to a tough start in season 11. The series was supposed to end in season 10, so it is clear the new stories for this season are awkward and a little messy at first.

However, “Chardee McDennis 2: Electric Boogaloo” still provides a sequel to one of the funniest It's Always Sunny episodes (from season 7). Season 11 also includes "Mac & Dennis Move to the Suburbs," scenes from which have provided the fodder for viral memes about dysfunctional relationships.

The most innovative episode of the season is inarguably "Being Frank," which is shot entirely from Frank Reynolds' perspective — leading to one of Danny DeVito's best performances in the series. Moreover, "The Gang Goes To Hell" is a memorable, thriller-inspired 2-part season finale. "Moyle vs. Ponderosa: The Trial of the Century" is also a great episode for long-time viewers as it delivers the statutes of Bird Law, which is something newer fans or casual fans would find completely baffling.

10 Season 10

Best Episode: Charlie Work

Every season of It’s Always Sunny In Philadelphia has at least one viral episode, but no other season premiere has inspired as many copycats as “The Gang Beats Boggs," the infamous airplane drinking competition. Meanwhile, “The Gang Goes On Family Fight" shines the public spotlight on It’s Always Sunny In Philadelphia's unusual family, with Keegan-Michael Key as the game show host tasked with reeling in the gang's non-family-friendly banter.

However, the peak of this season is undoubtedly "Charlie Work," in which a 7-minute continuous shot reveals how Charlie is the force keeping Paddy's Pub together. This is not only the season's best episode, but it is one of the best It’s Always Sunny In Philadelphia episodes in the show's entire run. Seeing Charlie Day mimic the entire tracking shot shows his immense talents as a star and also the director's keen eye for making it work.

9 Season 2

Best Episode: Mac Bangs Dennis' Mom

Every season of It’s Always Sunny In Philadelphia will always be compared to season 2, mainly because it featured the introduction of Danny DeVito as Frank, Dennis and Dee’s father. Undoubtedly, Frank has always been the single best improvement in the show. One example of Frank's contributions to the show is in "The Gang Exploits a Miracle," where Frank charges patrons to see a water stain in the office resembling the Virgin Mary.

Frank isn't the overblown unhinged manic personality that he becomes in later years, and here he is a little more of a wildcard, which is better for the character. Meanwhile, Charlie does as promised in "Charlie Goes America All Over Everybody's Ass." The finale, "Dennis and Dee Get a New Dad," actually establishes many of the key dynamics in the gang revolving around Frank being their collective father figure.

8 Season 13

Best Episode: Mac Finds His Pride

Every season of It’s Always Sunny In Philadelphia is surreal in some way, but season 13 just takes it to another level. In "The Gang Makes Paddy's Great Again," the first episode, Dennis gets replaced by a sex doll version of himself. Meanwhile, "The Gang Does a Clip Show" sees the gang's memories mixing with their fantasies, which includes a scene-by-scene recreation of a Seinfeld episode where Mac and Dennis both play Jerry.

It's Always Sunny in Philadelphia season 13 notably ends with "Mac Finds His Pride," which finally saw Mac coming into the greatness he always perceived in himself, culminating in the single most cathartic moment in the whole series. This episode did something that most It’s Always Sunny In Philadelphia failed to do, as it was not only funny but very sincere and delivered one of the best moments of the entire series. Other highlights include "Charlie's Home Alone" and "The Gang Wins the Big Game."

7 Season 16

Best Episode: Dennis Takes A Mental Health Day

After the bold Ireland-set season of It's Always Sunny, season 16 of the show returned to its roots for a more basic collection of episodes. The result is one of the best seasons of the show in recent memory with some episodes destined to become classics.

Even this deep into the series, the sitcom was still revealing hilarious new things like the fact that Charlie and Frank's apartment is actually a two-bedroom with a bathroom as well as the It's Always Sunny.

This was impressive, as the 16th season of the show remained beloved and critically acclaimed

Some of the episodes set up the comedy from the title alone, such as "Frank Shoots Every Member of the Gang." However, the funniest episode allowed Dennis to truly embrace his hilarious rage problems with the finale "Dennis Takes a Mental Health Day." This was impressive, as the 16th season of the show remained beloved and critically acclaimed, receiving yet another perfect 100% rating on Rotten Tomatoes.