2400 A.D. is a role-playing video game designed by Chuck Bueche and published by Origin Systems in 1988. It was originally released for the Apple II with a version for IBM PC compatibles later the same year. Poor sales resulted in the cancellation of both a Commodore 64 port and a sequel, 2500 A.D.

The player is an ordinary citizen who lives in the futuristic city Metropolis. The city has been conquered, and its population enslaved by an alien race known as Tzorgs. They have sent robots to maintain order in Metropolis, turning it into a police state. There are rumors of an underground resistance movement, but finding the resistance is dangerous, and being caught by the robots will lead to being thrown in prison...

The gameplay style is similar to the Ultima series, also from Origin Systems. The entire game is viewed from top-down perspective. The various commands (search, open, talk, etc.) are executed by pressing a correspondent key on the keyboard. Battles take place on the same screen as exploration, and require the player to press A (for "attack") and a directional key to aim at the enemy. The game is set entirely in the big city, with streets and buildings to explore, items and weapons to buy, and people to talk to.