Cassandra's Dream is a 2007 crime thriller drama film written and directed by Woody Allen. It stars Hayley Atwell, Colin Farrell, Sally Hawkins, Ewan McGregor and Tom Wilkinson. Shot in England, the film is a co-production between the United States, France, and the United Kingdom.

The film premiered in secret in Avilés, Spain, on 18 June 2007. It officially premiered at the 64th Venice International Film Festival on 2 September 2007 and was already in theaters in Spain by 3 November. The film had its North American premiere at the Toronto International Film Festival on 11 September 2007. Cassandra's Dream was released theatrically in France on 31 October 2007, in the United States on 18 January 2008, and in the United Kingdom on 23 May 2008.

Brothers Terry and Ian, who live in South London, were raised by their father, Brian, who runs a restaurant, and their mother, Dorothy, who taught her sons to look up to their uncle Howard, a successful plastic surgeon and businessman. He has opened clinics in Switzerland, the United States and, more recently, in China.

The brothers buy a sailboat at a low price, despite its near pristine condition. They name it Cassandra's Dream, after a greyhound that won Terry the money to buy the boat.

While driving home from a day's sailing in a borrowed car, Ian crosses paths with actress Angela Stark, with whom he becomes infatuated. After noticing her car has broken down, he stops to help her fix it. As a way to thank him, she gives Ian tickets to the play in which she is performing. After he attends the play, and despite Angela's already having a lover, she and Ian start dating.

Terry has a gambling addiction that sinks him deeper in debt. Ian wishes to invest in hotels in California to finance a new life with Angela. To overcome their financial problems, they decide to ask Howard for help. When Howard returns from a business trip to China, he agrees to help them, but asks for a favor in return: they must murder a man named Martin Burns. Howard faces imprisonment for unspecified crimes and his future is threatened by Burns, a former business partner who plans to testify against him. Howard asks his nephews to get rid of Burns, and in return he will reward them financially. After initial reluctance, the brothers agree.

In the ensuing days before the murder, while trying to come up with a plan, Ian fears Angela is sleeping with other people. He promises to give her a life in Hollywood if they treat their relationship as a serious, exclusive thing. To kill Martin, Ian and Terry eventually decide to make zip guns, untraceable and easily destroyed. Lying in wait in Burns' home, their plan is foiled when he arrives with a woman. Their resolve shaken, they leave and agree to commit the murder the next day.

The next day, after Martin visits his mother, Terry and Ian follow him and succeed in carrying out the murder. They later destroy the guns. Ian is content to move on as if nothing happened, but Terry is consumed by guilt and begins abusing alcohol and other drugs. His behavior frightens his fiancée, who tells Ian about the situation, saying that Terry believes he has killed someone. After Terry confides that he wants to turn himself in to the police, Ian goes to Howard for advice. They agree there is no alternative but to get rid of Terry. Ian plans to poison Terry during an outing on the boat. Unable to bring himself to kill his own brother, Ian attacks him in a fit of rage. In the chaos, Terry knocks Ian down the steps into the cabin, killing him.