The sixth season of the American television sitcom series It's Always Sunny in Philadelphia premiered on FX on September 16, 2010.

Later, the gang decides to buy a boat with the money made from their merchandise in "Paddy's Pub: Home of the Original Kitten Mittens," but, as usual, everything goes wrong.

This season also sees Dee becoming pregnant and every male panicking over who could be the possible father (with the surprise revealed to be Carmen at the end of the season), Charlie finally getting the respect he deserves during a scheme to throw a surprise party for him, and the gang getting lost in the woods on the way to Atlantic City.

The gang also puts a cynical spin on Christmas when it is discovered that all of their treasured memories of the holidays were masking the debauched events that happened around that time as well.

The website's critical consensus reads, "Cleverly folding Kaitlyn Olson's real-life pregnancy into the plot with characteristic perversity, It's Always Sunny's sixth season sees the Gang trying – and failing – to grow up.