Wedding Crashers is a 2005 American romantic comedy film directed by David Dobkin, written by Steve Faber and Bob Fisher, starring Owen Wilson, Vince Vaughn, Rachel McAdams and Isla Fisher with Christopher Walken, Bradley Cooper and Jane Seymour in supporting roles. The film follows two divorce mediators (Wilson and Vaughn) who crash weddings in an attempt to meet and seduce women. When they crash the wedding of the U.S. Treasury Secretary's daughter, they are unexpectedly invited to the family's home, where a weekend of farcical events changes their perspectives on love and marriage.

The film opened on July 15, 2005, through New Line Cinema to critical and commercial success, grossing $288.5 million worldwide on a $40 million budget. It was the 6th highest grossing film of 2005 in the United States and became the first R-rated comedy to make $200 million at the domestic box office. The success of the film has been credited with helping to revive the popularity of adult-oriented, R-rated comedies.

Best friends John Beckwith and Jeremy Grey are divorce mediators in Washington, D.C. who, in their spare time, crash weddings under false identities to meet and have sex with women. At the end of a season of successful crashes, Jeremy convinces John to crash the wedding of the eldest daughter of the U.S. Treasury Secretary, William Cleary. At the nuptials, the pair set their sights on Cleary's other daughters, Gloria and Claire. During the reception, Jeremy has sex with Gloria on a nearby beach; she tells him afterward that she was a virgin. Possessive and infatuated, Gloria tells Jeremy that she loves him. Meanwhile, John becomes smitten with Claire, the maid of honor, but is interrupted by her hotheaded boyfriend, Sack Lodge, who is unfaithful and disrespectful behind her back. Gloria invites John and Jeremy to an extended weekend retreat at their family compound in Maryland. Jeremy is anxious to escape from Gloria, but John overrules him and accepts in an effort to get closer to Claire.

John and Jeremy become acquainted with the Clearys. The Secretary's wife Kathleen comes on to John sexually while Gloria's brother Todd tries to seduce Jeremy during the night. Gloria continues to lavish sexual attention on Jeremy, massaging his penis at dinner and later tying his wrists and ankles to a bedframe and raping him. Sack also repeatedly injures Jeremy during a game of touch football. At dinner, John spikes Sack's wine with eye drops to make him sick and get more time to connect with Claire.

John and Claire continue to bond the next day during a sailing trip. The suspicious Sack takes John and Jeremy on a hunting trip and pranks them, shooting Jeremy in the buttocks. While Jeremy recovers, John and Claire go on a bike ride to a secluded beach. Claire finally admits she is not sure how she feels about Sack and kisses John passionately. Back at the Clearys' estate, Gloria tends to Jeremy's wounds and reveals to him that she lied about being a virgin. Jeremy realizes that he may be in love with Gloria. Later in the afternoon, Sack announces that he and Claire are getting married. Jeremy prompts John to forsake his pursuit of Claire so they can go home, but John refuses, stating that he is in love with her. While John is confessing his feelings to Claire, they are interrupted by Jeremy being chased out of the house at gunpoint. Sack, who has been investigating them, reveals John and Jeremy's real identities to the family. Disappointed, the Secretary tells them to leave.

Over the following months, John attempts to reach Claire, but she refuses to see him. Expecting Jeremy to aid him, he attempts to sneak into Claire and Sack's engagement party, but is caught and beaten by Sack. Confronting Jeremy about abandoning him, John learns that Jeremy has secretly continued his relationship with Gloria. Feeling betrayed and brokenhearted, John spirals into depression, crashes weddings alone, and becomes nihilistic and suicidal. As Sack and a reticent Claire plan their wedding, Jeremy proposes to Gloria and tries to ask John to be his best man, but John turns him away.

John visits Jeremy's former wedding-crashing mentor, Chazz Reinhold. Chazz, who lives with his mother as a middle-aged man, convinces John to crash a funeral with him. At the funeral, John reconsiders his belief in love and marriage after seeing the grieving widow. John rushes to Jeremy's wedding and joins them mid-ceremony. Claire is upset by his presence and begins to leave, prompting John to regret his past behavior and profess his love for her in front of the congregation. Sack mocks John and orders Claire to return to the altar, but she finally tells him that she can not marry him. After the Secretary stands by his daughter and John quips about Sack's temper, Sack tries to attack John, but Jeremy intervenes and knocks him out. As Jeremy and Gloria tie the knot, John and Claire share a kiss. After the wedding, the two couples drive away from the ceremony and discuss crashing another wedding together.

Arizona Senator and 2008 Republican presidential nominee John McCain and Democratic strategist and CNN contributor James Carville make a brief cameo appearance, when they are shown congratulating the secretary and his wife on their daughter's wedding.