X Japan (エックス・ジャパン, Ekkusu Japan) is a Japanese heavy metal band from Chiba, formed in 1982 by Yoshiki and Toshi. Originally named X (エックス, Ekkusu), the group achieved their breakthrough success in 1989 with the release of their second album Blue Blood. They started out mainly as a power/speed metal band, but later gravitated towards a progressive sound with an emphasis on ballads.

Besides being one of the first Japanese acts to achieve mainstream success while on an independent label, the group is widely credited as one of the pioneers of visual kei, a movement among Japanese musicians comparable to Western glam. In 2003, HMV Japan ranked the band at number 40 on their list of the 100 most important Japanese pop acts.