Kyoko Tonguu is a Japanese voice actress born on October 11, 1955, in Okayama, Japan. Her real name is Kyoko Miyagi, but she is professionally known by her stage name, Kyoko Tonguu. She is affiliated with the talent management agency Aoni Production.

Tonguu began her voice acting career in the early 1980s. A significant turning point came in the mid-1980s when she was cast as Kei, one of the two lead protagonists in the popular science fiction comedy series Dirty Pair. This role became one of her most iconic and enduring performances, which she reprised across various projects including the 1985 television series, multiple original video animations, and feature films like Dirty Pair: Project Eden and Dirty Pair: Flight 005 Conspiracy. During this active period of her early career, she was also known for her role as Nakamura in the 1987 cyberpunk film Black Magic M-66.

Throughout the 1980s and into the early 1990s, Tonguu built a substantial filmography, often voicing young boys and energetic characters. Her many roles from this era include Smith in Ginga Nagareboshi Gin, Sarumaru Sarutani in the Pro Golfer Saru series and its related specials, Joey in New Maple Town Stories, Aidor in Akū Daisakusen Srungle, and Manabu Noguchi in Kickers. She also lent her voice to characters in films such as Chibi in Demon City Shinjuku, Atenas in Xanadu Dragonslayer Densetsu, and Akio in Gegege no Kitarō: Yōkai Daisensō. Her last regular anime role before a career pause was Kikunosuke Abashiri in the 1991 series The Abashiri Family.

In 1992, Tonguu took a hiatus from voice acting and moved to Milan, Italy, following her husband's job transfer. She returned to Japan and resumed her career later in the same decade. Upon her return, her work shifted primarily towards dubbing foreign movies and television programs into Japanese. She did, however, return to anime for select projects. Notable credits from this later period include the role of Taichi in the 2006 film The Cake Tree in the Ruins, as well as parts in series like Mermaid Forest and the video game Star Fox: Assault.