Yūko Nagashima is a Japanese voice actress born on July 3, 1970, in Osaka Prefecture. She has been active in the entertainment industry since 1992 and is currently affiliated with the talent agency Amuleto, having previously worked with Aoni Production.

Nagashima developed an interest in the world of acting from a young age. While working part-time at a bookstore, she discovered a leaflet inviting students to learn acting and decided to pursue this opportunity. Her professional debut took place in 1992. She has expressed a strong preference for voice-over work over on-screen appearances.

Throughout her career, Nagashima has portrayed a wide range of characters in various anime series. She is known for her performance as Caldina in the fantasy series Magic Knight Rayearth and its sequel. She provided the voice for Erina Won in the science fiction series Martian Successor Nadesico and played the role of Mimori Kiryuu in the action series s-CRY-ed as well as its compilation films. Her role as Yayoi Aida, a reporter and statistician, in the sports anime Slam Dunk brought her considerable recognition.

Other notable television roles include Rina Takamiya in Saint Tail, Natsumi Ihata in Rizelmine, Ayumu Yamazaki in Peacemaker, Tsubaki in Naruto, Arbell in One Piece, and Reiko Sakai in Youre Under Arrest. She voiced the character Manemaneko in the Sailor Moon franchise and appeared in other series such as Ceres, The Celestial Legend, Eden's Bowy, Variable Geo, Non Non Biyori Repeat, and Marmalade Boy.

Beyond her anime work, Nagashima has an extensive career in video game voice acting. She is particularly recognized as the long-standing voice of Tina Armstrong in the Dead or Alive fighting game series, a role she has voiced since the first game in 1996 through Dead or Alive 6 and its various updates. She also voices the character Kunoichi in the Samurai Warriors and Warriors Orochi series. Her video game credits include Mio Stout in Atelier Ryza: Ever Darkness & the Secret Hideout, Milena in Destrega, and Kei Ayamine in Muv-Luv Alternative.

Nagashima is also a prolific dubbing artist, notably serving as the established Japanese voice for actress Sarah Jessica Parker in the series Sex and the City and subsequent films. Her dubbing work includes providing the Japanese voice for Elena Fisher in the Uncharted video game series.