Ryōko Tanaka (田中 涼子, Tanaka Ryōko, born July 28, 1973) is a Japanese voice actress from Tokyo.
She used to belong to the Arts Vision, Office Mori and Pro-Fit talent agency.
She is a native of Japan Narration Acting Institute.
She has a good relationship with Harumi Sakurai in the trade.
She is known for the alias as Hikaru Isshiki (Japanese: 一色 ヒカル).