The second season of the American television sitcom series 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.
The series' second season introduces veteran actor Danny DeVito portraying Dennis and Dee's father Frank, who moves in with temporary wheelchair user Charlie following a car accident, and blackmails his way into the group. Before production of the second season began, series creator Rob McElhenney found out that DeVito was a fan of the show and a friend of FX president, John Landgraf. McElhenney asked Landgraf to set up a meeting. McElhenney met DeVito at his home and pitched DeVito's character, Frank Reynolds. DeVito agreed to star in the show, but was only available for twenty days. To have Frank Reynolds in all ten episodes of the second season, all of DeVito's scenes were filmed before filming the remainder of the season.
<onlyinclude></onlyinclude>
The second season received positive reviews. On Rotten Tomatoes, it has an approval rating of 95% with an average score of 7.8 out of 10 based on 21 reviews. The website's critical consensus reads, "The Gang becomes complete with the addition of Danny DeVito, whose wily performance gives Always Sunny a new shine."
The season two episodes are presented in production order, rather than their original broadcast order.