<P> It's Always Sunny in Philadelphia is an American television black comedy sitcom that premiered on FX on August 4, 2005 . It moved to FXX beginning with the ninth season, and has remained there since . It was created by Rob McElhenney, who developed it with Glenn Howerton . It is executive produced and primarily written by McElhenney, Howerton, and Charlie Day, all of whom star alongside Kaitlin Olson and Danny DeVito . The series follows the exploits of "The Gang", a group of debauched self - centered friends who run the Irish bar Paddy's Pub in South Philadelphia . </P> <P> The series was renewed for a twelfth season that premiered on January 4, 2017 . On April 1, 2016, the series was renewed for a thirteenth and fourteenth season, which will tie it with The Adventures of Ozzie and Harriet as the longest running live - action sitcom in American TV history . </P> <P> The series follows "The Gang", a group of five depraved underachievers: twins Dennis Reynolds (Glenn Howerton) and Deandra "Sweet Dee" Reynolds (Kaitlin Olson), their friends Charlie Kelly (Charlie Day) and Ronald "Mac" McDonald (Rob McElhenney), and (from season 2 onward) Frank Reynolds (Danny DeVito), Dennis' and Dee's legal father . The Gang runs the dilapidated Paddy's Pub, an Irish bar in South Philadelphia . </P> <P> Each member of the gang shows varying degrees of dishonesty, egotism, selfishness, greed, pettiness, ignorance, laziness, and unethical behavior; they are often engaged in controversial activities . Episodes usually find them hatching elaborate schemes and often conspiring against one another and others for personal gain, vengeance, or simply the entertainment of watching another's downfall . They habitually inflict mental, emotional, and physical pain on each other and anyone who crosses their path . They also regularly use blackmail to manipulate one another and others outside of the group . </P>

Who is related in it's always sunny