Double Dragon is a 1987 beat 'em up video game developed by Technōs Japan and published by Taito for arcades. The game's development was led by Yoshihisa Kishimoto, and it is a spiritual and technological successor to Technos' earlier beat 'em up, Nekketsu Kōha Kunio-kun (1986), released outside of Japan by Taito as Renegade; Kishimoto originally envisioned it as a direct sequel and part of the Kunio-kun series, before making it a new game with a different cast and setting.

Double Dragon introduced several additions to the Kunio-kun belt scroll beat 'em up formula, such as a continuous side-scrolling world adding a sense of progression, two-player cooperative gameplay, the ability to arm oneself with an enemy's weapon after disarming them, and the use of cutscenes to give it a cinematic look and feel. The game's title is a reference to the two-player gameplay and Bruce Lee's martial arts film Enter the Dragon (1973), which was a major inspiration behind Kunio-kun and Double Dragon, while the game's art style and setting were influenced by the Mad Max films and the Fist of the North Star manga and anime series.

Double Dragon was one of the first successful beat 'em up games, becoming Japan's third highest-grossing table arcade game of 1987 before becoming America's highest-grossing dedicated arcade game in 1988 and 1989. It also received critical acclaim, with Electronic Gaming Monthly awarding it Game of the Year in 1988. Its success resulted in the creation of the Double Dragon franchise, including two arcade sequels and several spinoffs. It also ushered in a "golden age" for the beat 'em up genre, establishing the conventions for a wave of similar games from other companies during the late 1980s and 1990s. Home versions were released for the NES, Master System, Atari 2600, Atari 7800, Atari ST, Amiga, Amstrad CPC, Commodore 64, Game Boy, Sega Genesis, and Atari Lynx, among other platforms during the series' height of popularity. A remake titled Double Dragon Advance was released for the Game Boy Advance in 2003.

The game is displayed in a belt scroll format, like Kunio-kun. In contrast to the arena-like levels in Kunio-kun, Double Dragon takes place in a continuously side-scrolling world.

The player takes control of martial artist Billy Lee, or his twin brother Jimmy (also known as Hammer and Spike in the supplementary materials for the American arcade release), as they fight their way into the turf of the Black Warriors gang in order to rescue Billy's girlfriend, Marian. The player character has a repertoire of martial arts techniques which they can perform by using the joystick and three action buttons (kick, jump, and punch) individually or in combination. Techniques range from basic punches and kicks to more elaborate attacks such as throws and elbow strikes. When playing with another player, one can grab an opponent from behind, allowing the other to attack unimpeded; some enemies are able to do the same thing to the players. The player begins the game with a certain number of extra lives and a life gauge which depletes as the player takes hits, and must complete each stage within a time limit. One life is lost if either the life gauge or timer reaches zero, or if the player character falls off the bottom of the screen or into a hole, river, or bed of spikes.

Certain enemies carry melee weapons, which can be knocked out of their hands and picked up to use against them. Available weapons include baseball bats, whips, throwing knives, and dynamite; in addition, rocks, oil drums, and boxes can be found in certain places.

The game is divided into four different stages or "missions", which consist of a city slum, a factory, a forest, and the gang's hideout. The first three levels takes place in a single long map, with the change in background music indicating the presence of a boss character. When a boss is defeated, the remaining underlings will retreat and the player character will enter an automatic transition sequence where he will walk into the next stage. There's also another transition sequence near the end of the third stage just as the player reaches the entrance of the gang's hideout. The fourth and final stage is set inside the hideout on a separate map as the players fight their way through numerous traps until reaching the main hall where Willy awaits. The Double Dragon title theme plays during this period. The game normally ends if Willy is defeated by a single player, but if both Lee brothers manage to complete the game together, they will be forced to fight each other in order to determine who will win Marian's affections. Both life gauges are refilled, any extra lives are taken away, and the timer is reset for this fight.

The Double Dragon duo were actually unnamed when the original arcade game was initially released in Japan, although the names Hammer and Spike were given to them in the cabinet and promotional flyer produced by Taito for the overseas version. The names Billy and Jimmy Lee were first established in the Famicom/NES version of the first game.