Wonder Boy is a 1986 platformer video game published by Sega and developed by Escape (now known as Westone Bit Entertainment).

It was the first in the long-running Wonder Boy series of games and was followed up by five sequels, Wonder Boy in Monster Land, Wonder Boy III: Monster Lair, Wonder Boy III: The Dragon's Trap, Wonder Boy in Monster World and Monster World IV. It was also the basis for the Adventure Island series.