Ryōtarō Okiayu (置鮎 龍太郎, Okiayu Ryōtarō, November 17, 1969) is a Japanese voice actor, who was born in Kitakyushu, Fukuoka Prefecture, and raised in Osaka. He has been active since 1989, and is currently affiliated with Aoni Production.

He was part of the voice actor unit E.M.U (Entertainment Music Unit) with fellow voice actors Hikaru Midorikawa, Hideo Ishikawa, Nobutoshi Canna (known then as Nobutoshi Hayashi) and Daisuke Sakaguchi. The unit was formed in 1995, and disbanded in 2000.