Kumiko Nishioka (西岡 久美子, Nishioka Kumiko, born 1954) is a Japanese mathematician at Keio University. She specializes in transcendental numbers, and is known for her research related to the theory of Mahler functions[1][2][3] and Painlevé transcendents.[4] In 1996 she published the first comprehensive text on transcendence of Mahler functions, Mahler Functions and Transcendence, extending and generalizing Mahler's method.[5] Her husband Keiji Nishioka is also a mathematician, and a coauthor.