Kataoka Seiko

 (片岡聖子) is a Japanese singer, former actress, former Japanese idol and a former member of All Nighters and its subgroup Oazuke Sisters.

She joined All Night Fuji in 1983, and joined the idol sub-unit Oazuke Sisters in May 1984. She stayed until it disbanded later that year due to Inoue Akiko leaving All Night Fuji. She left the All Nighters around the time All Night Fuji restructured in early 1985.

After that she landed small acting and MC-ing roles. After that, she married and retired. In 2013, she returned to singing as part of the revival group Okaeri Sisters that perform sporadically.