Here's some background and inside jokes to help fill in some of the gaps for viewers who don't watch both Philly-based shows.

Of course, Liam McPoyle is rocking an eyepatch because ... Mac writes a letter to Chase Utley in It's Always Sunny In Philadelphia and gives it to Dee, asking her to make sure he gets it.

Wednesday night’s midseason premiere episode of Abbott Elementary, aptly titled “Volunteers,” finally delivered its highly anticipated crossover encounter with the cast of FXX’s It’s Always Sunny in ...

How It’s Always Sunny in Philadelphia Got Its Mojo Back Twelve seasons in, the FXX sitcom has a bona fide breakthrough. Episode 9 A Cricket’s Tale It’s Always Sunny in Philadelphia Recap ...

The cast of It’s Always Sunny in Philadelphia made its way to the ABC show, which is set in Philly, for the crossover episode of comedy writers’ dreams. The brief promo for the Jan. 8 ...

There's something about FXX's Rob McElhenney, Charlie Day, Glenn Howerton, Kaitlin Olson, and Danny DeVito-starring It's Always Sunny in Philadelphia that's bothered me over the past few years.

The cast of It’s Always Sunny in Philadelphia invades Abbott Elementary in the first teaser trailer for the comedy crossover event. It’s pretty uncommon to see shows on one network crossover ...

“Sweet Baby Jesus and the grown one too.” The ‘Abbott Elementary’ and ‘It’s Always Sunny in Philadelphia’ crossover episode (the first of two) is officially happening. Airing January ...

Mac, Dennis and Dee try out for the Philadelphia Eagles. Also interested in becoming an Eagle is Liam and Ryan McPoyle's brother, Doyle. Dennis joins up with an environmentalist group, but his ...

The 'Abbott Elementary' episode of the ‘It’s Always Sunny in Philadelphia’ and 'Abbott Elementary' crossover just aired. When will the ‘It’s Always Sunny' episode air? Here's what we know.