Riko Koike is a Japanese voice actress and singer born on 1 January 1991 in Fukui, Fukui Prefecture. She is affiliated with the talent agency Millennium Pro. Inspired to pursue a career in voice acting after watching the 1994 film Mobile Fighter G Gundam, she attended Tokyo Woman's Christian University and the Arcadia Voice Actor Academy.

Koike's professional career began in 2015 after she won the Developer Award at a public audition for the game Chain Chronicle, which led to her debut role as Paru in that title. Her early years involved voicing characters in various projects, including the television anime Dream Festival! and Magic-kyun! Renaissance in 2016.

Her first leading role in a television anime series came in 2018 when she was cast as Caracal in Kemono Friends 2. She later reprised this role for the 2020 video game adaptation of the series. In 2021, Koike was cast as the major character Myamu in the television anime Waccha PriMagi!. For this series, she also performed as part of the group that sang the second ending theme song, Check One Two. In 2023, she voiced the protagonist in the television anime adaptation of the picture book Sore Shikanai Wake Nai Deshō.

Other notable voice roles in anime include Mai Sunagawa in Harukana Receive and a young Lucio Cortes in Rusted Armors: Daybreak. Her work in video games spans several titles, with roles in Chaos Dragon, Duel Masters Place, and Omega Labyrinth Life, among others. Beyond her voice work, Koike's personal interests include plastic modeling and railway research.