Day of the Dead is a 1985 American post-apocalyptic zombie horror film written and directed by George A. Romero, and produced by Richard P. Rubinstein. The third film in Romero's Night of the Living Dead series, it stars Lori Cardille, Terry Alexander, Joseph Pilato, Jarlath Conroy and Richard Liberty as members of a group of survivors of a zombie apocalypse sheltering in an underground bunker in Florida, where they must determine the outcome of humanity's conflict with the undead horde. Romero described the film as a "tragedy about how a lack of human communication causes chaos and collapse even in this small little pie slice of society".

Work on Day of the Dead began shortly after the release of the previous film in the series, Dawn of the Dead (1978), but was halted when Romero began work on other projects. It was developed as part of a three-film deal with that film's distributor, United Film Distribution Company (UFDC); Romero elected to make the two other projects outlined in the deal, Knightriders (1981) and Creepshow (1982), first. Although the filmmaker was given final cut privilege, the screenplay was rewritten multiple times due to UFDC's concerns that Romero's ambitious original vision ― which he described as "the Gone with the Wind of zombie films" ― would need to be shot with the intention of receiving an R rating from the Motion Picture Association of America to ensure its commercial viability; Romero elected to make the film on a lower budget and release it without a rating. Day of the Dead was filmed in fall 1984, with above-ground scenes in the cities of Fort Myers and Sanibel and underground scenes near Wampum, Pennsylvania. Tom Savini returned to provide the film's special make-up effects; he was assisted by a team of artists that included Greg Nicotero and Howard Berger, who later became known for their work on the television series The Walking Dead.

Day of the Dead premiered at Hicksville, New York on June 30, 1985, and grossed $34 million worldwide against a budget of approximately $4 million. Although the make-up effects were praised, the film initially did not match the critical and commercial success of its predecessors; the series did not see another installment until the 2005 release of Land of the Dead. Reception of the film has improved with time, and Romero deemed it to be his personal favorite film in the original Dead trilogy. Like its predecessors, Day of the Dead has garnered a cult following and inspired numerous parodies and homages.

The film was remade twice: the first is the 2008 film of the same name, and the second is Day of the Dead: Bloodline (2018). A television series based on the film began airing on Syfy in 2021, while a stand-alone sequel, Night of the Living Dead II, is in active development.