Machiko Washio is a Japanese actress and voice actor born on June 2, 1949, in Kanagawa Prefecture. She began her career in 1966 and has been active across stage, television, and film for several decades. She is affiliated with the talent agency SIS company.

Her entry into voice acting came through her work in theatre. She was cast as the voice of Sakura in the popular anime series Urusei Yatsura after being noticed by a producer during a stage performance. This role, which she played from 1981 to 1986, remains one of her most recognized performances in animation. She later reprised the role of Sakura for several animated films, including Urusei Yatsura: Only You in 1983 and Urusei Yatsura 2: Beautiful Dreamer in 1984.

In addition to her long-running role in Urusei Yatsura, Washio has contributed her voice to other notable anime projects. She played Tamiko Yomota in the original video animation Gosenzo-sama Banbanzai! from 1989 to 1990 and in its 1990 theatrical compilation film, Maroko. Her filmography also includes roles in two celebrated Studio Ghibli films: she was the elementary school teacher in My Neighbor Totoro and voiced the character Okami in Castle in the Sky.

While she is known for these iconic voice roles, Washio's career is primarily that of a versatile actress with an extensive body of work in live-action television and film. She has had prominent roles in numerous taiga dramas and asa-dora (morning dramas) for NHK, and is particularly well known for her long-running role as Kuzuoka in the popular Ooku television series, which she played from 2003 to 2005. Her career as a live-action actress has continued into the 2020s, with roles in the 2021 asadora Come Come Everybody and the 2024 drama The Tiger and Her Wings.