Season 0 of It's Always Sunny in Philadelphia premiered on September 4, 2007.

Bonus features from Season DVD sets and TV promos.

Season 1 of It's Always Sunny in Philadelphia premiered on August 4, 2005.

The first season of It's Always Sunny in Philadelphia, premiered on FX on August 4, 2005. The season contains 7 episodes and concluded airing on September 15, 2005.

Season 2 of It's Always Sunny in Philadelphia premiered on June 29, 2006.

The second season of It's Always Sunny in Philadelphia, premiered on FX on June 29, 2006. The season contains 10 episodes and concluded airing on August 17, 2006.

Season 3 of It's Always Sunny in Philadelphia premiered on September 13, 2007.

The third season of It's Always Sunny in Philadelphia, premiered on FX on September 13, 2007. The season contains 15 episodes and concluded airing on November 15, 2007.

Season 4 of It's Always Sunny in Philadelphia premiered on September 18, 2008.

The fourth season of It's Always Sunny in Philadelphia, premiered on FX on September 18, 2008. The season contains 13 episodes and concluded airing on November 20, 2008.

Season 5 of It's Always Sunny in Philadelphia premiered on September 17, 2009.

The fifth season of It's Always Sunny in Philadelphia, premiered on FX on September 17, 2009. The season contains 12 episodes and concluded airing on December 10, 2009.

Season 6 of It's Always Sunny in Philadelphia premiered on September 16, 2010.

The sixth season of It's Always Sunny in Philadelphia, premiered on FX on September 16, 2010. The season contains 14 episodes and concluded airing on December 9, 2010 with the hour-long Christmas special. An additional episode called "The Gang Gets Successful" was produced for this season, but was not aired, despite scenes from the episode being included in promotional material for season 6. It was later re-edited with new scenes to create the Season 7 episode "How Mac Got Fat".

Season 7 of It's Always Sunny in Philadelphia premiered on September 15, 2011.

The seventh season of It's Always Sunny in Philadelphia, premiered on FX on September 15, 2011. The season contained 13 episodes, and concluded airing on December 15, 2011. The episode "How Mac Got Fat" includes scenes produced during season 6 that featured Mac, before he got fat.

Season 8 of It's Always Sunny in Philadelphia premiered on October 11, 2012.

The eighth season of It's Always Sunny in Philadelphia, premiered on FX on October 11, 2012. This season consisted of 10 episodes, and concluded airing on December 20, 2012.

Season 9 of It's Always Sunny in Philadelphia premiered on September 4, 2013.

The ninth season of It's Always Sunny in Philadelphia, premiered on FXX on September 4, 2013. This season consisted of 10 episodes, and concluded airing on November 6, 2013.

Season 10 of It's Always Sunny in Philadelphia premiered on January 14, 2015.

The tenth season of It's Always Sunny in Philadelphia, premiered on FXX on January 14, 2015. This season consisted of 10 episodes, and concluded airing on March 18, 2015.

Season 11 of It's Always Sunny in Philadelphia premiered on January 6, 2016.

The eleventh season of It's Always Sunny in Philadelphia, premiered on FXX on January 6, 2016. This season consisted of 10 episodes, and concluded airing on March 9, 2016.

Season 12 of It's Always Sunny in Philadelphia premiered on January 4, 2017.

In season twelve, Mac, Dennis, Charlie, Dee and Frank tackle all new adventures that include going to a waterpark, dealing with a Wolf Cola PR nightmare, and actually spending a whole day tending bar!

Season 13 of It's Always Sunny in Philadelphia premiered on September 5, 2018.

The Gang returns... mostly... in Season 13. Mac, Charlie, Dee, and Frank return to their duplicitous, scheming ways at Paddy’s Pub, while Dennis takes on the new role of father in North Dakota. Even without Dennis, the Gang has its hands full as Charlie hopes to have a child with The Waitress, Mac sets out to understand his newfound sexuality, Dee takes feminism to new heights, and Frank goes to great lengths for the Gang to experience the greatest moment in Philadelphia sports history – an Eagles Super Bowl victory.

Season 14 of It's Always Sunny in Philadelphia premiered on September 25, 2019.

The 14th season guns for the Best 14th Season accolade as the Gang goes to extremes for the role – Mac learns a new language, Charlie does a period piece, Dennis attempts a one-act play, Dee cuts her hair, and Frank performs a death scene.

Season 15 of It's Always Sunny in Philadelphia premiered on December 1, 2021.

In season fifteen, the gang finds themselves at a crossroads in this strange new world in the wake of Covid-19 and all things 2020. The rules are changing quicker than anyone can keep up with, despite herculean efforts from Mac, Charlie, Dennis, Dee, and Frank to continue business as usual. They must also now face the music and decide who they’ll become in the cultural upheaval that is 2021.

Season 16 of It's Always Sunny in Philadelphia premiered on June 7, 2023.

In Season sixteen, it’s a challenge for Ronald “Mac” MacDonald, Charlie Kelly, Dennis Reynolds, Dee Reynolds, and Frank Reynolds who yearn for the past as they attempt to survive in 2023. This year alone, Mac battles with allergies and long-distance dating, Charlie takes on his long-forgotten sisters, Dee fights for rent control and women’s athletics, Frank wrestles for his gun, and Dennis struggles to improve his mental health. At the end of the day, they’re navigating 2023 with 16 years of baggage as a few figures from their past rear their heads.