Who's That Girl is a 1987 American screwball comedy film directed by James Foley and written by Andrew Smith and Ken Finkleman. It stars Madonna and Griffin Dunne, and depicts the story of a street-smart girl who is falsely accused of murdering her boyfriend and is sent to jail. After being released, she meets a man, who is supposed to make sure she gets on her bus back to Philadelphia, and convinces him to help her catch those responsible for her confinement. While searching for the embezzler, they fall in love with each other.

After the failure of her 1986 film Shanghai Surprise, Madonna decided to sign up for another comedy film titled Slammer, which was later renamed Who's That Girl. However, she had to convince both Warner Bros. and the producers of the film that she was ready for the project. Madonna enlisted her friend James Foley to direct the film. Shooting began in New York in October 1986, and continued until March 1987. Production was halted during December due to snowfall in New York. Madonna utilized the time to work on her next tour and the soundtrack of the film.

The film was released on August 7, 1987, and was a box office bomb, grossing only $2.5 million in its first week, with its final domestic total being about $7.3 million on a budget between $17 million and $20 million. Critics were highly disappointed with the film, and Foley's direction. Madonna's accompanying Who's That Girl World Tour went on to be a critical and commercial success, grossing a total of US$25 million, and playing in front of audiences totaling 1.5 million people. The soundtrack also enjoyed commercial success, with the title track becoming Madonna's sixth number one single on the US Billboard Hot 100 record chart.