When Harry Met Sally... is a 1989 American romantic comedy drama film written by Nora Ephron and directed by Rob Reiner. It stars Billy Crystal and Meg Ryan as Harry and Sally, respectively. The story follows the title characters from the time they meet in Chicago and share a drive to New York through twelve years of chance encounters in New York City. The film addresses the question "Can men and women ever just be friends?"

Ideas for the film began when Reiner and Penny Marshall divorced. An interview Ephron conducted with Reiner provided the basis for Harry. Sally was based on Ephron and some of her friends. Crystal came on board and made his own contributions to the screenplay. Ephron supplied the structure of the film with much of the dialogue based on the real-life friendship between Reiner and Crystal. The soundtrack consists of standards from Harry Connick Jr., with a big band and orchestra arranged by Marc Shaiman. For his work on the soundtrack, Connick won his first Grammy Award for Best Jazz Male Vocal Performance.

Columbia Pictures released When Harry Met Sally in selected cities, letting word of mouth generate interest, before gradually expanding distribution. The film grossed $92.8 million in North America, and was released to critical acclaim. Ephron received a British Academy Film Award, an Oscar nomination, and a Writers Guild of America Award nomination for her screenplay. The film is ranked 23rd on AFI's 100 Years... 100 Laughs list of the top comedy films in American cinema and number 60 on Bravo's "100 Funniest Movies". In early 2004, the film was adapted for the stage in a production starring Luke Perry and Alyson Hannigan.

In 2022, the film was selected for preservation in the United States National Film Registry by the Library of Congress as being "culturally, historically, or aesthetically significant".