Yūko Nishi is a Japanese voice actress known for her work in anime and OVA productions during the late 2000s and early 2010s. She was born on April 12 in Osaka Prefecture, Japan. Nishi is a graduate of the 81 Acting Institute in Tokyo and was formerly affiliated with the talent agency 81 Produce. Her professional activities have been recorded from 2007 onward. She speaks the Osaka dialect and has listed swimming and playing the Electone electronic organ as her hobbies and special skills.

Nishi’s voice acting career includes several supporting roles in television anime series. In 2008, she appeared in the series Allison & Lilia as a boy and in the children's anime ChoroQ Deke System Q Fighters! as Kyuuta. That same year, she had a role as a schoolgirl in To Love-Ru. She contributed to multiple seasons of the sports anime MAJOR, playing various minor characters including fans of the character Shiigeno, a boy, and the role of Peter in the fourth, fifth, and sixth seasons. Other television credits include a child in Mokke, a boy in Metal Fight Beyblade, a friend and a girl in Gokujo!! Mecha Mote Iinchou Second Collection, and a role in the series Kamen Rider Dragon Knight.

Beyond television, Nishi performed voice work for the original video animation Yanase Takashi Märchen Theater, a collection of short anime based on picture books by Takashi Yanase. In this OVA, she took on several episodic roles. In the segment Dejatan Mimi Tan Pontan, she voiced a tanuki. In the segment Robo-kun to Kotori, which was later released in theaters in 2012 as part of the Yanase Takashi Theater film, she played the role of the monkey. She also voiced a duck in another segment of the same OVA collection. Her work in dubbing includes providing Japanese voices for foreign television series such as the Korean drama The Legend of the Condor Heroes, Thomas and Friends, and the American medical drama Nurse Jackie.

A voice actress named Yuuko Nishi is also credited as a character in the anime series A Channel, but this is a fictional character and not a role performed by the voice actress Yūko Nishi.