The sequel to the 2009 film The Hangover and the second installment in The Hangover trilogy, the film was directed by Todd Phillips, who co-wrote the script with Craig Mazin and Scot Armstrong, and stars Bradley Cooper, Ed Helms, Zach Galifianakis, Ken Jeong, Jeffrey Tambor, Justin Bartha, and Paul Giamatti.

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

[a] To avoid what happened in Las Vegas, Stu does not allow his three best friends, Doug Billings, Phil Wenneck and Alan Garner to throw him a bachelor party.

Through a tip from Doug (who left the campfire earlier and stayed at the resort), they go to a police station to pick up Teddy, but are given a wheelchair containing an elderly Buddhist monk.

After Phil is treated at a clinic, Alan confesses that he had drugged some of the marshmallows with muscle relaxers and his ADHD medication to sedate Teddy, but accidentally mixed up the bags.

Fong is about to cancel the wedding when Stu arrives, makes a defiant speech, and rejects being a boring dentist and instead insists that he is wild.

Mike Tyson reprises his role as himself and sings a cover of the 1984 Murray Head song "One Night in Bangkok" for the movie.

"[21] Also by March, Galifianakis, Helms, Bradley Cooper, and Justin Bartha completed negotiations and signed deals to reprise their roles in the sequel.

"I remember we did this photo shoot for Vanity Fair and that was when we first talked about a sequel in a realistic way; and we were all in the room together afterwards and we were saying 'here's the choice: do we stray from the structure or do we run straight for it?'

[23] In July 2010, it was confirmed that the film would indeed be set in Thailand and earlier comments made by Phillips denying such reports were a deliberate case of misdirection.

[25] In October 2010, Phillips confirmed that the film would take place in Bangkok and Los Angeles and that Galifianakis, Cooper, Helms and Ken Jeong would be returning.

[5] On a budget of $80 million,[26] principal photography began on October 8, 2010, in Ontario, California with the first images of production being released a few days later.

Phillips stated: "I thought Mel would have been great in the movie and I had the full backing of [WB president] Jeff Robinov and his team.

[32] In November 2010, it was reported that Jamie Chung had been cast in the film as Stu's fiancée as well as it being renamed, The Hangover Part II.

"[10] Also in December, Australian stuntman Scott McLean was seriously injured in a traffic accident while filming a stunt sequence near Bangkok.

The project marks the fourth collaboration between Beck and Philips, who also worked together on School for Scoundrels, The Hangover and Due Date.

[36] In April 2011, Variety reported that Liam Neeson's cameo as a Bangkok tattoo artist had been accidentally cut and Nick Cassavetes had been re-cast in the role.

Warner Bros. released a statement saying, "In our haste to meet the placement schedule for this trailer, we failed to properly vet the final version with the MPAA.

[43][44] Warner Bros. said it would digitally modify the tattoo in the home video release if no agreement was reached;[45] it settled with Whitmill on June 20 under undisclosed terms.

[46] In 2011, Scott McLean, an Australian stuntman who was injured and suffered brain damage while filming in Bangkok sued Warner Bros.

The case was settled out of court for an undisclosed sum, though several years later McLean was still fighting Warner Bros, who were disputing ongoing medical costs incurred in treatment for the injuries he sustained at work.

[53] On May 27, the film took an additional $30.0 million, dropping only 5 percent from the takings of the previous day and becoming the highest-grossing Friday for a live-action comedy.

[53] In total, the film accrued $60.3 million[59] from its Friday-through-Monday opening weekend, more than tripling the international gross of The Hangover's debut in the same territories.

Australia accrued a gross of $12.1 million to replace Sex and the City in the country as the highest-grossing opening for an MA-rated film—no-one under the age of 15 permitted.

The site's critical consensus reads, "A crueler, darker, raunchier carbon copy of the first installment, The Hangover Part II lacks the element of surprise—and most of the joy—that helped make the original a hit.

[73][74] Andrew Barker of Variety gave the film a negative review, stating, "The stock dismissal 'more of the same' has rarely been more accurately applied to a sequel than to The Hangover Part II, which ranks as little more than a faded copy of its predecessor superimposed on a more brightly colored background".

[76] Roger Ebert of the Chicago Sun-Times gave the film two stars out of four stating, "The Hangover Part II plays like a challenge to the audience's capacity for raunchiness.

Director Todd Phillips raised concerns after he joked that Crystal had become addicted to cigarettes after learning to smoke them for the film.

Philips later explained that Crystal never actually held a lit cigarette on the film's set and the smoke was added digitally in post-production.

Among them is a photo where Phil points a gun at Chow's head, mimicking Eddie Adams' famous photograph of the Execution of Nguyễn Văn Lém during the Vietnam War.