By-Sexual (stylized as BY-SEXUAL) was a Japanese visual kei punk rock band from Osaka. They were active from 1988 to 1995, when vocalist Sho left the band and they went on hiatus. In August 1996, the remaining members restarted the group under the name By-Sex (stylized as BY-SEX) with Ryo changing to vocals and guitar. In February 1998, Nao left and the group disbanded.
On September 3, 2011, By-Sexual reunited for a show at Shinagawa Stellar for the victims of the 2011 Tōhoku earthquake and tsunami. Around the same time, Ryo and Den teamed up with their former Zigzo bandmate Sakura to formally restart By-Sex.
By-Sexual was formed in April 1988 in Osaka. That year they released the demo "Bad Boy Blues" on Free-Will records. They signed to Pony Canyon and in February 1990 they released their major debut, "So Bad Boy". Their first album Culture Shock followed in April. It reached number 6 on the Oricon chart and was named one of the top albums from 1989-1998 in a 2004 issue of the music magazine Band Yarouze.