"Swan Song" is the fifth-season finale of The CW television series Supernatural. It is the 22nd episode of the fifth season, and is the show's 104th episode overall. Steve Boyum directed the episode with teleplay written by series creator Eric Kripke and story written by Eric Gewirtz. The episode aired on Thursday, May 13, 2010, and concluded the series' originally slated storyline. The narrative follows the series' protagonists Sam and Dean Winchester —brothers who travel the continental United States hunting supernatural creatures—as they attempt to stop the Apocalypse.

The fifth season of Supernatural, an American dark fantasy television series created by Eric Kripke, premiered September 10, 2009, and concluded on May 13, 2010, on The CW. Season five regular cast members include Jared Padalecki, Jensen Ackles and Misha Collins, who was promoted to series regular this season. After the conclusion of this season, series creator Eric Kripke stepped down as showrunner. The fifth season was released on DVD and Blu-ray in region 1 on September 7, 2010. The season follows Sam and Dean as they set out to take down Lucifer, whom Sam had inadvertently released from Hell at the end of the previous season.