Claim: The Hangover Part III includes Bradley Cooper, Ed Helms, Zach Galifianakis, Justin Bartha, and Ken Jeong, Jeffrey Tambor, Heather Graham, Mike Epps, Melissa McCarthy and John Goodman.

The Hangover Part III is a 2013 American comedy film 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 , Justin Bartha , and Ken Jeong . The supporting cast includes Jeffrey Tambor , Heather Graham , Mike Epps , Melissa McCarthy and John Goodman with Todd Phillips directing a screenplay written by himself and Craig Mazin . The film follows the `` Wolfpack '' -LRB- Phil , Stu , Doug , and Alan -RRB- as they try to get Alan the help he needs after facing a personal crisis . 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 . The film was released on May 23 , 2013 .