Yūko Sumitomi (also written as Yuuko Sumitomo) is a Japanese voice actress and narrator affiliated with the agency Aoni Production. She was born on July 11 in Tokyo, Japan, and has an A blood type. Her vocal range spans from C to F, covering two octaves and a fourth.

Sumitami's career in voice acting began around 1990. One of her early television anime roles was in the long-running series Chibi Maruko-chan. Throughout the 1990s, she appeared in a variety of shows, including Jungle King Tar-chan, Sailor Moon R, Marmalade Boy, and the fourth installment of GeGeGe no Kitaro.

The late 1990s and 2000s saw Sumitomo take on more prominent roles. She voiced Minami Shimahara, the eldest of three sisters who inherit a giant guardian deity, in the 1998 mecha series Neo Ranga. For this role, she also participated in the show's opening and ending theme songs alongside her co-stars. She played the part of Chiaki Shinjō in the visual novel and OVA adaptation Canary. Her other anime credits from this period include Laura Hope in FireStorm, Miku Munakata in Happy Seven, and Alice in Fantastic Children. She has also had guest roles in major series such as One Piece, where she voiced a character named Lily, and Ghost in the Shell: Stand Alone Complex.

In video games, Sumitomo is known for several long-running character portrayals. She has voiced Millia Rage, an assassin who controls her hair as a weapon, in the Guilty Gear fighting game series since its debut in 1998. She is also the voice of Zhenji, the wife of the warlord Cao Pi, in the Dynasty Warriors series and its various crossover titles, including Warriors Orochi. Her other notable game roles include Priscilla F. Neumann in Star Ocean: The Second Story, Undine in the Tales of series, and Aurelia Le Guin in later entries of The Legend of Heroes: Trails of Cold Steel subseries.

Beyond character work, Sumitomo has an extensive career as a narrator for a wide range of Japanese television programs, including news shows, variety programs, and educational series like NHK's Shumi Time. She has also performed voice-over work for foreign films and dramas, such as Revolutionary Road.