Ninja Gaiden is an action video game released for the Game Gear in 1991 by Sega with license from Tecmo. It stars Ryu Hayabusa and is part of the Ninja Gaiden series, although it features a plot not connected to any of the other Ninja Gaiden games.

Gameplay is in many ways similar to the NES and Master System games with minor differences in mechanics. Jumping is more like moon jumping and the sword slash is quicker and has a wider range. Ryu can also scale walls and edges. There four different secondary weapons. Ryu's "spiritual strength" (called Force) can go up to 99.