Emperor Ninken (仁賢天皇, Ninken-tennō) was the 24th emperor of Japan, according to the traditional order of succession. Historians consider details about the life of Emperor Ninken to be possibly legendary, but probable. The name Ninken-tennō was created for him posthumously by later generations.

No certain dates can be assigned to this emperor's life or reign. The conventionally accepted names and sequence of the early emperors were not to be confirmed as "traditional" until the reign of Emperor Kammu, who was the 50th monarch of the Yamato dynasty.