Ryouko Tanaka is a freelance seiyuu born in Tokyo in 1973. She's good friends with fellow seiyuu Harumi Sakurai.
She is primarily known for her work in Visual Novels (particularly in eroge, under the name "Hikaru Isshiki").
- Abe no Seimei and Hercules in Eiyuu Senki: The World Conquest
- Ayame Sasaki in Crescendo ~Eien Dato Omotte Ita Ano Koro~
- Hikari Kuroda in School Days
- Hinata Kagura in H2O: Footprints in the Sand
- Jane Doe/Eileen Cartwright in Dies Irae
- Kagome Hinaori in Coμ - Black Dragon in a Gentle Kingdom
- Kannei in KoihimeMusou
- Massea in Ys V
- Maya Tsukuyomi in Muv-Luv
- Seiso Hazakura and Haou in Maji de Watashi ni Koi Shinasai!
- Spetto in Fairy Tail
- Tomoyo Sakagami in CLANNAD: Tomoyo After (as opposed to Houko Kuwashima, who voices her everywhere else)
- Touka Nishikujou in Rewrite
- Tsubomi in Shuffle
- Yahiro Ifukube in Yosuga no Sora
- Yuiko Kurugaya in Little Busters!
- Yumika Midorishita in Yumina The Ethereal
- Yumiko Sasaki in Grisaia no Kajitsu (and all following sequels and spin-offs)