Mikio Masuda is a Japanese jazz and jazz fusion keyboardist.
Largely self-taught, Masuda played bass at the age of 16, before switching to piano and performing in various clubs in Osaka. In 1969, he moved to Tokyo. He played from the early 1970s in the Japanese jazz scene, notably in a quartet with Motohiko Hino, Shunzo Ohno and Terumasa Hino, performing in 1973 at the International New Jazz Meeting at Burg Altena, Germany. In 1974 he recorded his debut album Trace for East Wind Records. This was followed by the 1976 jazz-fusion album Mickey's Mouth.
In the following years he also worked with Kosuke Mine, Hidefumi Toki, Takao Uematsu, Hiroshi Murakami, Kazumasa Akiyama, Kazumi Watanabe and Eri Ono. After moving to New York City in 1978, he created the album Corazón, and worked in NYC, notably with David Matthews. In two other New York stays, he created the trio album Black Daffodils in 1996 with Ron Carter and Lewis Nash, and Blue Dumplings in 1998 with Ron Carter and Grady Tate. In the field of jazz he was involved between 1972 and 1998 in 46 recording sessions, most recently with Chie Ayado.