Luna Sea (stylized as LUNA SEA) is a Japanese rock band formed in Kanagawa Prefecture in 1986. Due to the use of makeup and costumes early in their career and their widespread popularity, they are considered one of the most successful and influential bands in the visual kei movement. Throughout the mid-1990s they used significantly less makeup, and after a one-year break in 1997, came back with a more mainstream alternative rock style and toned down their on-stage attire. They disbanded in 2000. In 2003, HMV Japan ranked Luna Sea at number 90 on their list of the 100 most important Japanese pop acts.

Initially founded in 1986, by bassist J and rhythm guitarist Inoran while in high school, the band was originally called Lunacy. In 1989 they recruited lead guitarist Sugizo, drummer Shinya and vocalist Ryuichi, a lineup that has remained the same. They released a few demo tapes prior to renaming themselves Luna Sea and releasing their self-titled debut album in 1991. The band achieved their breakthrough success with a sold-out tour in 1991, which helped them get a contract with MCA Victor, and with the release of their second album Image (1992), which reached number nine on the Oricon music chart. Following the critically acclaimed albums Eden (1993), Mother (1994) and Style (1996), the band switched to Universal in 1998 and released their best-selling studio album, Shine. In late 2000, after their seventh studio album Lunacy, Luna Sea disbanded.

Luna Sea reunited for a one-off reunion concert in 2007 at the Tokyo Dome, and again in 2008 for the hide memorial summit. In 2010 the group officially reunited and held a world tour. Three years later they released their first new album in thirteen years, A Will. Their ninth album, Luv, followed four years later in 2017. At the end of 2019, their tenth album Cross, co-produced by Steve Lillywhite, became their first to top Billboard Japan.