Dragon Slayer (ドラゴンスレイヤー, Doragon Sureiyā) is an action role-playing game, developed by Nihon Falcom and designed by Yoshio Kiya. It was originally released in 1984 for the PC-8801, PC-9801, Sharp X1 and FM-7, and became a major success in Japan. It was followed by an MSX port published by Square in 1985 (making it one of the first titles to be published by Square), a Super Cassette Vision by Epoch in 1986 and a Game Boy port by the same company in 1990 under the name Dragon Slayer I (ドラゴンスレイヤーI, Doragon Sureiyā Wan). A remake of Dragon Slayer was also included in the Falcom Classics collection for the Sega Saturn.

Dragon Slayer began the Dragon Slayer series, a banner which encompasses a number of popular Falcom titles, such as Dragon Slayer II: Xanadu, Sorcerian, and Legacy of the Wizard.