Gyarados (ギャラドス Gyaradosu^?, /ˈɡɪərədoʊs/) is a Pokémon species in Nintendo and Game Freak's Pokémon franchise. Created by Ken Sugimori, Gyarados first appeared in the video games Pokémon Red and Blue and subsequent sequels, later appearing in various merchandise, spinoff titles and animated and printed adaptations of the franchise. Gyarados is voiced by Unshō Ishizuka in both Japanese and English media. Known as the Atrocious Pokémon, Gyarados is the evolved form of Magikarp and it is well known in the Pokémon world for its fierce temper as well as its reputation for causing nothing but destruction so much so that once it has worked itself into a frenzy, it will not calm until everything around it has been destroyed.

Gyarados appears multiple times in the anime under various trainers such as Misty, Lance, Crasher Wake, and Nurse Joy. Two different Gyarados appear in the Pokémon Adventures manga. One is originally owned by Misty, but is traded between Red andBlue. The other is a red Gyarados that is owned by Silver. Since it appeared in the Pokémon series, Gyarados has received generally positive reception. It has been featured in several forms of merchandise, including figurines, plush toys, and thePokémon Trading Card Game. Gyarados has been described as both one of the most well known and most powerful Pokémon.