Momoko Ishii(石井 桃子,Ishii Momoko?, March 10, 1907 – April 2, 2008) was a distinguished Japanese author and translator of children's books.
Ishii was born in Urawa, Saitama, and graduated from the Japan Women's University with an English literature degree. While working as an editor at Iwanami Shoten Publishers, she decided to become a children's writer after reading Winnie-the-Pooh by English author A. A. Milne, which she translated in 1940. Her first book as an author, Non-chan kumo ni noru (Non-chan rides on a cloud) was published in 1947; a best-seller, it was made into a movie in 1955. All told, she published nineteen books of her own and 120 translations for children.
Ishii received many honors in her life, including the Minister of Education Award for Promotion of Art for Non-chan kumo ni noru (1951), the Kikuchi Kan Award for achievement and contribution to the postwar world of children's literature (1953), the Itochu Memorial Foundation Award for Distinguished Service to Children's Bunko (1984), the Japanese Art Academy Award for achievement in the world of children's books (1993), and the 1994 Yomiuri Prize for her two-volume autobiographical novel Maboroshi No Akai Mi (Memoirs of a childhood) in 1995. In 1997 she became a member of the Japanese Art Academy, the first member from the field of children's literature.