Luckily, every season is filled with laughs and great satirical commentary, but only one season was truly perfect. Check out the rankings below, and sound off in the comments at @Popdust if you disagree.
Season 1
A show's debut season is never its finest, but Season 1 of It's Always Sunny was particularly horrendous. Frank Reynolds was nowhere to be seen, and Rob McElhenney wrote the characters to be so despicable and irredeemable that the show didn't feel like it would have a future.
Charlie wasn't a shameless potty-mouthed rat killer, Dennis was painted as a mere narcissist rather than as the sociopathic control freak we know and love, Mac wasn't yet a closeted homosexual, and Dee was just the butt of everyone's jokes and insults. Season 1 almost got the show canceled entirely.
Season 3
As with many good sitcoms, Season 3 is usually around when the writing starts to pick up steam, and S3 of It's Always Sunny was no different. With that said, the gang had a monumental 15-episode order to fill and churned out some pretty weak filler episodes.
"The Gang Dances Their Asses Off" season finale was particularly tepid, finding Dennis and Dee and the gang embroiled in a Paddy's Pub dance competition against their rivals, and "Dennis Looks Like a Registered Sex Offender's" sole punchline is that Dennis looked like a registered sex offender. But the show also had some great standouts, such as "The Gang Gets Invincible," where the group tries out for the Philadelphia Eagles, as well as "The Gang Gets Held Hostage," where the repulsive (but hilarious) McPoyles take control of Paddy's Pub and hold the gang hostage at gunpoint. Regardless, a 15-episode order proved to be too big a task for the gang, as Season 3 was filled with a lot of duds.
Season 14
The newest season of It's Always Sunny isn't that funny. There are moments of truly amazing banter, where the actors are locked into their characters and where their collective chemistry is just radiant, but as far as plot development goes, Season 14 starts to show the inevitable aging of It's Always Sunny.
The season's debut episode, "The Gang Gets Romantic," is one of It's Always Sunny's most incoherent plot lines, with the gang getting obsessed over AirBnb. Dee and Dennis choose to house a seemingly irreconcilable married couple in their home, while Charlie and Frank meet two Austrian backpackers who crash at their house. In another episode, Frank is obsessed with the color blue for some reason. A few moments of fun aside, Season 14's tried-and-true It's Always Sunny gags start to lose their bite.
Season 11
There are few It's Always Sunny episodes better than "Mac and Dennis Move to the Suburbs." The duo accepts a bet to live a month outside of Philly in exchange for free rent. The episode's subsequent shenanigans – which include eating a dog, terrorizing a neighbor, and Dennis succumbing to hilarious road rage – offer non-stop laughs that make it an absolute standout. Still, it's odd that this gem is lodged into a season filled with mostly flat gags.
"Frank Falls Out the Window" finds Frank with amnesia, but instead of doing something new and exciting with that premise, the writers chose to rehash old It's Always Sunny episodes that "haven't happened yet" and serve that as the punchline. Season 11's two-part finale "The Gang Goes to Hell" didn't need to be a two-parter, and other episodes like "Dee Made a Smut Film" and "The Gang Hits the Slopes" offer promising premises only to lose steam at their halfway marks.
Season 13
While Glenn Howerton's notable absence in a handful of Season 13 episodes caused the gang's banter and overall writing to dip in parts, Season 13 was actually a great step forward for Sunny. With the #MeToo Movement and Trumpism in full swing, the writers had a lot of great and uncomfortable scenarios to help them illuminate the gang's worst qualities.
As we've seen throughout the years, the gang regularly degrades women, but in "Time's Up for The Gang," their antics finally catch up with them, as the gang is forced to go to a #MeToo-laden sexual harassment seminar. The gang additionally explores Trumpism in "The Gang Make's Paddy's Great Again," and Mac finally embraces his pride and quells Frank's prejudice via a beautiful interpretive dance on the moving season finale "Mac Finds His Pride." While a few episodes lose their steam, Season 13 felt like a necessary evolution for a sitcom that had been treading water the last few years.
Season 2
Frank's debut season helped the series pick up a considerable amount of steam and kicked off so many great moments. "The Gang Goes on Welfare," "Hundred Dollar Baby," "Mac Bangs Dennis' Mom," "The Gang Gives Back" are all hilarious and classic misadventures.
The addition of Frank saved It's Always Sunny from cancelation, and he gave the series a noticeable morale boost and undeniable sheen. The only downfall here is that Frank's character wasn't quite written out to be as wry and self-destructive as we know him to be now, but thankfully he would only go on to become more deplorable.
Season 10
Season 10 was a mixed bag compared to the show's earlier misadventures, but for as late in the game as it was, Season 10 was remarkably entertaining. "The Gang Beats Boggs" was one of the best late-season Sunny episodes, with the gang immersed in a years-old drinking competition while on a commercial flight to California. On "Frank Retires," the gang is forced to think of a future without Frank, which breeds some hilarious results. Still, other episodes like "Mac Kills His Dad" are entirely forgettable.
Season 9
While the series premiere had the lowest number of U.S. viewers to date thanks to FXX trickery, the 9th season of It's Always Sunny was filled with meta pop culture commentary and hilarious gags. "The Gang Tries Desperately to Win an Award" served as a satirical commentary on the way TV shows are chosen for awards, while episodes like "The Gang Broke Dee" and "Mac Day" find Dee and Mac in very different circumstances than past seasons.
And of course, "The Gang Gets Quarantined" is a timeless episode as it follows the gang quarantining in the bar to stop the spread of the flu. This episode in particular has seen a massive resurgence thanks to 2020 global crisis. However, episodes like "The Gang Makes Lethal Weapon 6" feel like unnecessary filler, and "The Gang Squashes Their Beefs" offers a fantastic set-up with boring results.
Season 8
While we'd all like to unsee Charlie and Dee hooking up in Season 8, the eighth outing for the gang was full of twists and surprises. "The Maureen Ponderosa Wedding Massacre" was a hilarious take on the Zombie horror movie genre, and the gang's ludicrous plan to upend the trash industry boasted some hilarious results on "The Gang Recycles Their Trash." Not to mention, the whole episode is a meta-examination of what happens when a show reaches its eighth season.
While gems are present, episodes like "Charlie Rules the World" and "Pop Pop: The Final Solution" do nothing with their compelling subject matter – euthanasia and MMORPGs – and "Charlie's Mom Has Cancer" is just a rehash of the season 1 episode "Charlie Has Cancer."
Season 12
The 12th season of It's Always Sunny was fairly unremarkable. It's not that the season didn't possess funny moments, but the unfunny moments were almost unbearable. The musical premise of "The Gang Turns Black" had the potential to be stellar, but it turns out sending a senile old white man to dismantle racism isn't that funny, no matter how you spin it.
"Old Lady House: A Situation Comedy" is one of the series' most aimless episodes, the main conflict being that the gang can't decide whether comedies are funnier with a laugh track or without. "Making Dennis a Murderer" is filmed in a Making A Murderer-style documentary for some reason, and "A Cricket's Tale" doesn't feature the gang at all but instead focuses entirely on the series least exciting character, Cricket. However, the Season 12 finale contains good laughs and also leaves the fate of Dennis Reynolds up in the air, which was a surprising but refreshing character development.
Season 7
Mac's unnecessary weight gain for Season 7 served as a perfect set-up for a nearly flawless 13-episode run, the only true outlier being "Frank's Brother," an unnecessary flashback episode that features Frank's brother, a character who never appears again in the It's Always Sunny universe.
But the dud is redeemed by memorable outings like "The Gang Goes to the Jersey Shore" and "The High School Reunion," not to mention "The Gang Gets Trapped," where the gang gets stuck inside a house they're trying to rob after the owners come home unexpectedly. Great writing, and one delicious rum ham, make Season 7 one of the most iconic in the series.
Season 6
The only episodes that kept Season 6 from being perfect were "Charlie Kelly: King of the Rats" and "Mac's Mom Burns Her House Down," two totally funny episodes that were just not as funny as the perfect string of episodes that came before them. From shotgun weddings to gay rights to buying a boat, the first half of season 6 is full of non-stop laughs and unpredictable shenanigans that test the wits (or lack there of) of our favorite deranged alcoholics.
All of it is then tied together perfectly by a string of hilarious Christmas episodes that have now taken on memorable legacies of their own, especially during the holidays.
Season 4
Opening with an episode that turns Dee and Charlie into cannibals, Season 4 was one of the most plot-driven seasons of the show, with some of the series' best writing that perfectly captured the sitcom's dark humor. Episodes like "Mac's Banging the Waitress" add a hilarious layer to every character as they try to keep Charlie from finding out that Mac slept with The Waitress.
Meanwhile, other set-ups like "Who Pooped the Bed?" and "Dennis Reynolds: An Erotic Life" get just as disgusting and creepy as the titles suggest. Not to mention, Season 4 is closed out by "Nightman Cometh," the most well-known It's Always Sunny episode in history. The sole episode keeping this season from the number 1 spot is "The Gang Cracked The Liberty Bell," a flashback episode that at times struggles to stay afloat with all its Revolutionary-era thematic material.
Season 5
Every episode of Season 5 is flawless, from The Waitress getting married to the gang trying to exploit the mortgage crisis to Frank's first intervention. There is so much comedic gold in Season 5 that it's impossible to pick one episode over another. It's all brought together in the end by "The Gang Reignites The Rivalry," which features the legendary "Flipadelphia" drinking competition that was recently brought back to life after the state flipped for Biden in this year's election.
