The Hangover Part III is a 2013 American action comedy film and the sequel to The Hangover Part II (2011), both produced by Legendary Pictures and distributed by Warner Bros. Pictures. It is the third and final installment in The Hangover trilogy. The film stars Bradley Cooper, Ed Helms, Zach Galifianakis, Ken Jeong, Jeffrey Tambor, Heather Graham, Justin Bartha, and John Goodman with Todd Phillips directing a screenplay written by himself and Craig Mazin.

The film follows the "Wolfpack" (Phil, Stu, Doug, and Alan) as they try to get Alan the help he needs after facing a personal crisis, after the bachelor party in Bangkok. However, things go awry when an incident from the original film comes back to haunt them.

The Hangover Part III was announced days before the release of The Hangover Part II and Mazin, who co-wrote Part II, was brought on board. In January 2012, the principal actors re-signed to star. In March 2012, Warner Bros. announced a U.S. Memorial Weekend release. The supporting roles were cast between June and September 2012. Principal photography began in September 2012 in Los Angeles, California before moving to Nogales, Arizona and Las Vegas, Nevada, concluding that November. The film had its world premiere on May 13, 2013, in Los Angeles, California, and was theatrically released worldwide on May 24, 2013, by Warner Bros. Pictures. At the box office, The Hangover Part III earned $362 million against a production budget of $103 million. It received generally negative reviews from critics.