It's Always Sunny in Philadelphia (IASIP) first premiered on FX in 2005, and with its 16th season, it has become the longest-running live-action sitcom ever – and with another two already ordered, it's unlikely to end anytime soon. It stars Charlie Day, Glenn Howerton, Rob McElhenney, Kaitlin Olson, and Danny DeVito as egotistical friends often described as "the worst people in the world" who own the unsuccessful Paddy's Pub in Philly.

Known as "The Gang," the group gets up to a lot, from numerous scams to their own musicals. No matter what they're doing, it's practically guaranteed to be both ridiculous and hilarious, and some of its most memorable moments have gone on to become commonly used memes. The show has also pushed boundaries with the way it has at times tackled topical issues with its signature dark humor. With over 100 episodes, plenty of which rank on IMDb with a 9 or higher, there's no shortage of entertaining schemes from the best It's Always Sunny episodes. As fans begin the long wait for the already-confirmed Season 17 of Always Sunny, it's the perfect time to dive back into some favorites from previous years. The highest-rated and best episodes of It's Always Sunny in Philadelphia are always an excellent starting point for binge-watching the hilarious sitcom.

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15 "The Gang Solves the Gas Crisis" (Season 4, Episode 2)

IMDb Rating: 9.1/10

When Mac, Dennis, and Charlie put their heads together, they realize they can solve the gas crisis by buying gasoline, storing it in Paddy's basement, and then selling it later for a higher price. This turns disastrous, of course, when they realize how difficult it is to purchase and store gasoline in barrels. Meanwhile, Dee and Frank spy on Dee and Dennis' biological father, who they suspect is donating their mother's money.

Nothing goes right for the gang in this classic episode from what is still one of the best seasons of Always Sunny, and they end up ruining some lives along the way, too. There are some clear highlights, like Frank's obsession with waterboarding, the trio's presentation to the bank, and – most importantly – Charlie's numerous "wild card" moments that showcased a surprisingly zanier side to the already-wacky character.

14 "Time's Up for the Gang" (Season 13, Episode 4)

IMDb Rating: 9.2/10

When Paddy's Pub ends up on a list on the Internet called "Worst Bars For Women to Frequent," the gang has to attend an anti-harassment seminar to get the bar off of it. Mac, Charlie, Frank, and Dennis are annoyed about the entire thing, while Dee is excited and feels like she has an advantage over the group (and other male attendees).

A reference to the Time's Up and Me Too movement, "Time's Up for the Gang" pokes fun at some attitudes towards anti-harassment efforts. By showing the obscene and misogynistic humor the group has gotten used to, the episode emphasizes how normalized this kind of behavior can be. And viewers certainly won't forget Dennis' surprising role revealed towards the end, too.

13 "The Gang Tries Desperately to Win an Award" (Season 9, Episode 3)

IMDb Rating: 9.2/10

In "The Gang Tries Desperately to Win an Award," the group does exactly what the title says and goes on a challenging yet hilarious journey in an attempt to win recognition for their bar. After visiting the year's top bar, they realize they have to make a few changes and decide to host an "industry night" to increase their chances of success.

Things predictably go terribly wrong and escalate to gut-busting levels as the gang is unable to contain their chaotic selves. Aside from mocking stereotypical sitcoms (seen in the top bar, with perfect lighting, canned laughter, and cheesy moments), it also serves as a meta-comment on Always Sunny's lack of awards. The episode also features one of the best musical moments in IASIP, thanks to Charlie's song about spiders deep in his soul.

12 "Dennis Takes a Mental Health Day" (Season 16, Episode 8)

IMDb Rating: 9.2/10

Audiences finally learn exactly how Dennis manages his emotions despite the mess he constantly has to deal with, thanks to one of the best new episodes of It's Always Sunny, "Dennis Takes a Mental Health Day." It starts out when Dennis' high blood pressure makes his doctor worried during a physical exam, which he brushes off because he can simply "command" it to go down. After receiving an annoying call from the rest of the gang back at the bar, Dennis decides to take a mental health day.

Every new event during his mental health day only seems to contradict the purpose of the break and make Dennis feel worse, especially after dealing with apps and cars and missing phones. Soon, the IASIP episode spirals into absurdity, on levels never previously attempted by the show – it pays off, and has to be seen to be believed.

11 "CharDee MacDennis: The Game of Games" (Season 7, Episode 7)

IMDb Rating: 9.2/10

To combat boredom, the gang takes a break from their outrageous schemes and plays a Game of Games that they entirely made up. It’s called CharDee MacDennis, a combination of the creators’ names and a combination of all their favorite board games, from trivia and puzzles to "emotional battery and public humiliation," and all involving alcohol. And although it has a time limit of 15 minutes, there are numerous stoppages, making it last much longer in reality, and the official rules are convoluted.

Of all the things the gang gets up to, a board game should be the most normal and tame, and yet it manages to serve as a great example of how terrible they all really are. The game was revisited in Season 11’s "Chardee MacDennis 2: Electric Boogaloo," when the gang pitched it to an executive.

10 "The Gang Goes to the Jersey Shore" (Season 7, Episode 2)

IMDb Rating: 9.2/10

Dee and Dennis have fond memories of the Jersey Shore thanks to parts of their younger years being spent there. They decide to take Mac, Charlie, and Frank along in "The Gang Goes to the Jersey Shore" and end up finding a much darker and more dangerous place than they expected. Mac and Frank end up floating in the ocean with their "rum ham" and Charlie spends a drug-fueled night with The Waitress.

An all-around uproarious episode, the Jersey Shore storyline introduced fans to the beloved "rum ham," which has spawned numerous memes. There is also no shortage of iconic moments from the episode, which include Charlie's sunblock drink, what they find under the boardwalk, and Dee's unfortunate mishap with her braided hair and an amusement park ride.

9 "A Very Sunny Christmas" (Season 5, Episode 13)

IMDb Rating: 9.2/10

Dennis and Dee confront Frank about their past Christmas experiences and decide to teach him a lesson. Meanwhile, The gang questions each other’s traditions – Mac learns that his childhood traditions weren’t quite what they appeared to be at the time, and Charlie realizes something about the multiple Santas that used to visit his house on Christmas morning.

Christmas episodes are a sitcom staple, as are retellings of Charles Dickens’ classic A Christmas Carol, comedic or otherwise, and It’s Always Sunny does it wonderfully. One of the funniest moments is Mac’s home videos of Christmas, where it’s revealed that his family was actually breaking into other people’s houses and opening and stealing their presents before they woke up. But the true highlight is while Dennis and Dee try to get Frank’s former colleagues to say negative things about him, he is very obviously hidden inside a couch – and then bursts out of it totally naked.

8 "Sweet Dee's Dating a R******d Person" (Season 3, Episode 9)

IMDb Rating: 9.2/10

In one of IASIP's most controversial episodes, Dee starts dating a local rapper who Dennis thinks has an intellectual disability. Meanwhile, Mac, Dennis, Charlie, and Frank start a band, even though they can’t agree on which genre to play and none of them know how to play any instruments. When Dennis and the gang tell Dee that she's dating someone with a disability, she can't get it out of her head and lets it ruin the relationship.

Despite its problematic title, which creator Glenn Howerton regrets and finds offensive, the episode is a fan favorite. It’s notable for laying the groundwork for Charlie’s musical, "The Nightman Cometh," with his song and its eyebrow-raising lyrics about the character. It's also memorable for the hilarious way Dee's now-ex gets back at her with a scathing song about how judgemental she is.

7 "Mac Bangs Dennis' Mom" (Season 2, Episode 4)

IMDb Rating: 9.2/10

The episode title about sums it up – Mac sleeps with Dennis and Dee’s mom, Barbara, after she seduces him to get back at Frank for dating again, leading Dennis to retaliate. Meanwhile, Charlie devises a plan to get closer to The Waitress, roping Dee into the equation and making a messy web of lies.

The episode plays with common sitcom tropes dealing with schemes and pushes them to their absurd, very It’s Always Sunny limit. It even offers some unexpected twists – though not always comedic ones – and introduces the gang’s mothers (whom they try to sleep with but thankfully mostly fail), which might explain a lot. Its abrupt ending is also the perfect gut-busting punchline to the entire bizarre circus of sex and deceit, with Charlie, unfortunately, at the worst end of it.

6 "The D.E.N.N.I.S. System" (Season 5, Episode 10)

IMDb Rating: 9.3/10

Dennis shares with the gang his foolproof method of hooking up with women. Dee doesn’t think Dennis can win over the same woman twice and sets out to prove her wrong, then discovers Mac and Frank have methods of their own and that they swoop in on Dennis' conquests after he essentially ghosts them. Meanwhile, Dee's so bothered by the whole thing that she begins to question her own relationship and whether her boyfriend has used similar tactics on her, ultimately tanking a good, genuine relationship.

Although the D.E.N.N.I.S. system is about as terrible as one would expect – and not actually foolproof – involving plenty of dishonesty and manipulation, the scenes of the plan in action are entertaining, and the whole thing ends in the kind of wonderful and ridiculous chaos only It's Always Sunny can present.

5 "Hero or Hate Crime?" (Season 12, Episode 6)

IMDb Rating: 9.4/10

Frank saves Mac’s life by yelling a slur at him before a piano can fall on him, and the gang enlists the help of a professional arbiter to determine which of them is the rightful owner of a scratch-off lottery ticket Mac had at the time. The professional arbiter is understandably confused about their passion for what is likely a worthless ticket. At the same time, they debate whether Frank’s actions and choice of words make him a hero or a hatemonger.

While “Hero or Hate Crime?” provides plenty of It’s Always Sunny’s signature humor, it also has its sincere moments, in particular when Mac comes out as gay – and doesn’t deny it later, as he has in past episodes. This moment alone makes it fair to call this one a Mac-centered episode of IASIP, and an undeniably great one, too.

4 "Mac and Dennis Move to the Suburbs" (Season 11, Episode 5)

IMDb Rating: 9.4/10

Displeased with the Philadelphia housing market – notably, high costs and lack of space – Dennis and Mac go to the suburbs to find a new place to live after wearing out their welcome living with Dee. Naturally, what starts as domestic bliss spirals into mayhem. As Mac and Dennis begin to adopt a stereotypical husband and wife role, all the problems that come with it rise to the surface, and soon, they can't stand the boredom.

Is there a place where the gang – “city scum,” as Frank puts it – could possibly fit in less than the suburbs? “Mac and Dennis Move to the Suburbs” presents the two not as roommates, but rather partners in a bad marriage in a horror movie that’s getting worse by the second, with Dennis becoming full of rage and Mac losing his grip.

3 "The Gang Goes to a Water Park" (Season 12, Episode 2)

IMDb Rating: 9.5/10

In one of the most rewatchable Always Sunny episodes, the gang decides to spend a day in a water park, but as can be expected, they each have an ulterior motive. Dennis finds a protégé and Frank and Charlie are determined to ride everything, no matter what it takes to make that happen, while Mac and Dee get stuck in a tube slide meant for children, not adults.

“The Gang Goes to a Water Park” has plenty of fantastic moments, especially with the group split up. This presents plenty of opportunities for trouble and hilarity, from a pileup of kids and a trickle of urine in the slide with Mac and Dee to Frank wrecking his back by going down a new slide that wasn’t ready for the public yet and didn’t have any water. Plus, it's satisfying to see Dennis get outsmarted by a teenage girl.

2 "The Nightman Cometh" (Season 4, Episode 13)

IMDb Rating: 9.7/10

In the Season 4 finale (and one of the most well-loved and best IASIP episodes), Charlie turns his song “Nightman” into a full rock opera with the gang in its starring roles, who all have strong opinions about their roles. These strong opinions cause them to clash during production, infuriating Charlie in the process. In the end, Charlie uses the show to propose to The Waitress, who emphatically turns him down.

What a way to end a season. “The Nightman Cometh” is one of the most famous episodes of It’s Always Sunny, and fans undoubtedly know every word of the musical’s songs. Everything about the musical is hilarious, from its very amateur production quality to Frank’s memorable mispronunciation of “boy’s soul” as “boy’s hole.” It was even turned into an actual live musical.

1 "Charlie Work" (Season 10, Episode 4)

IMDb Rating: 9.8/10

Paddy’s Pub is due for a health inspection, and Charlie is dead set on making sure it passes. Just after he asks Frank to keep the place empty for the day, Charlie enters the bar to find the chaotic, messy scene of the gang in the middle of a scam involving live chickens. Once again, it's up to him to make sure the bar doesn't get shut down, and nobody appreciates his efforts.

The episode title, “Charlie Work,” is a reference to all the janitorial and maintenance work Charlie takes care of that the rest of the group is unwilling to do. The episode is critically acclaimed and regarded as the best in the series, and it’s fun to watch Charlie’s concern over the inspection and his frantic attempts to make sure it passes – he's a very different Charlie from the incompetent one audiences usually see. The best Charlie episode on Always Sunny is also notable for a 10-minute-long shot that further highlights the frantic and stressful days the character is so used to experiencing.

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