(500) Days of Summer is a 2009 romantic comedy-drama film. It was written by Scott Neustadter and Michael H. Weber, directed by Marc Webb, produced by Mark Waters, and stars Joseph Gordon-Levitt and Zooey Deschanel. Using a nonlinear narrative structure, the story is based upon its male protagonist and his memory-driven look at a failed relationship. Principal photography began in April 2008 in Los Angeles, California.

As an independent production, it was picked up for distribution by Fox Searchlight Pictures and premiered at the 2009 Sundance Film Festival. It was a hit with audiences and received a standing ovation at the festival. It later went on wide release in the US on August 7, 2009, on September 2, 2009, in the UK and Ireland, and on September 17, 2009, in Australia.

The film went on to achieve widespread success. It garnered critical acclaim and became a successful "sleeper hit", earning over $60 million in worldwide returns, far exceeding its $7.5 million budget. Many critics lauded the film as one of the best from 2009, seeing it featured in many year end lists and drawing comparisons to other acclaimed films such as Annie Hall, High Fidelity, and Eternal Sunshine of the Spotless Mind.

The film also received numerous awards and nominations; including Scott Neustadter and Michael H. Weber receiving the 2009 Satellite Award for Best Original Screenplay and the Independent Spirit Award for Best Screenplay. Notable nominations included two at the 67th Golden Globe Awards, for Best Picture (Musical or Comedy), and a nomination for Joseph Gordon-Levitt for Best Actor (Musical or Comedy).

The film is presented in a nonlinear narrative, as it jumps from various days within the 500-day span of Tom and Summer's relationship; this summary is a linear version of the events of the film.
On January 8, Tom Hansen meets Summer Finn, the new assistant to his boss. Tom trained as an architect but works as a writer at a greeting card company, living in Los Angeles. Following a karaoke night, Tom's co-worker, McKenzie, lets slip that Tom is attracted to Summer. Over the next few months Summer and Tom grow closer, despite Summer making it clear to Tom that she does not believe in true love, and does not want a boyfriend.
Tom shows Summer his favorite spot in the city, which looks out over a number of buildings he likes, although the view is spoiled by parking lots. After several months dating, Tom gets into a fight with a guy chatting up Summer, and they have their first argument. On day 290, Summer and Tom split up after they see The Graduate, a film which Tom thinks shows true love. Tom does not take the break up well, and Tom's friends call his younger sister, Rachel, to calm him down.
Summer quits the greeting card company. Tom's boss moves him to the consolations department, as his depression is not suitable for happier events. Months later, as Summer and Tom attend the wedding of a co-worker, they dance at the wedding and Summer catches the bouquet. They sit next to each other on the journey home and Summer invites Tom to a party at her apartment. Tom attends the party and sees that Summer is wearing an engagement ring. Upon seeing this, he leaves the party. Tom enters a deep depression, only leaving his apartment for alcohol and junk food. After a few days, he returns to work hungover and quits his job. He sets about re-applying himself to architecture, makes a list of firms, and begins to attend interviews.
On day 488, Summer sees Tom at his favorite spot in the city and they talk. Tom states his lack of understanding towards her actions, but ultimately wishes Summer well. Twelve days later, on Wednesday, May 23, he attends a job interview and meets a girl who is also applying for the same job. Before entering the interview, he makes a date to have coffee with her afterward. He asks her for her name, and she replies, "Autumn".