Back to the Future is a 1985 science fiction adventure film directed by Robert Zemeckis, co-written by Bob Gale and produced by Steven Spielberg. The film stars Michael J. Fox as Marty McFly, as well as Christopher Lloyd, Crispin Glover, Lea Thompson and Thomas F. Wilson. Back to the Future tells the story of Marty McFly, a teenager who is accidentally sent back in time from 1985 to 1955. He meets his parents in high school, accidentally attracting his mother's romantic interest. Marty must repair the damage to history by causing his parents to fall in love, while finding a way to return to 1985.

Zemeckis and Gale wrote the script after Gale mused upon whether he would have befriended his father if they attended school together. Various film studios rejected the script until the box office success of Zemeckis' Romancing the Stone, and the project was set up at Universal Pictures with Spielberg as executive producer. Eric Stoltz was originally cast as Marty McFly when Michael J. Fox declined as he was busy filming the TV series Family Ties, but during filming Stoltz and the filmmakers decided Stoltz was miscast so they asked Fox again and he managed to work out a timetable so he gave enough time and commitment to both: the subsequent recasting meant the crew had to race through reshoots and post-production to complete the film for its July 3, 1985 release date.