Phil Wenneck, Stu Price and Alan Garner, travel to Las Vegas for a bachelor party to celebrate the impending marriage of their friend, Doug Billings.

Lucas and Moore wrote the script after hearing how a friend of executive producer Chris Bender went missing following his bachelor party in Las Vegas.

[2] After Lucas and Moore sold it to Warner Bros. for $2 million,[3] Phillips and Jeremy Garelick rewrote the script to include a tiger, a subplot involving a baby and a police cruiser, and real-life boxer Mike Tyson.

After the previous film's bachelor party in Las Vegas, Stu takes no chances and opts for a safe, subdued pre-wedding brunch.

Warner Bros. hired Phillips and Scot Armstrong to write a sequel to The Hangover after a trailer brought down the house at ShoWest in April 2009, two months before the film was released.

Still lacking a sense of purpose, Alan has ditched his meds and given in to his natural impulses until the untimely death of his father forces him to finally re-evaluate his lifestyle and seek the help he needs.

[10] The principal actors signed on in January 2012 and production began in September 2012 in Los Angeles, California, before moving to Nogales, Arizona, and Las Vegas, Nevada.