Masa Nakayama (中山 マサ, Nakayama Masa, January 19, 1891 – October 11, 1976) was a Japanese politician and educator who was the first woman appointed to the Cabinet of Japan when she became Minister of Health and Welfare in 1960.^[1]

Nakayama was born Masa Iida-Powers in Nagasaki, the daughter of Rodney H. Powers, an American businessman who had settled in Nagasaki in the 1860s, and his Japanese partner, Naka Iida. Masa attended Kwassui Jogakko, a mission school run by American Methodist missionaries. In 1911, she moved to the United States where she enrolled at Ohio Wesleyan University,^[2] graduating in 1916. Returning to Japan, she had a distinguished career as a high school and college educator prior to the outbreak of World War II.^[3] In 1923, Nakayama married Fukuzō Nakayama, a lawyer and politician who served in the lower house from 1932 to 1942, and later in the upper house after World War II.^[4]

In 1947, she was elected as a member of the House of Representatives in the Diet, representing the second district of Osaka Prefecture.^[4] In 1960, she became the first woman appointed to the Cabinet of Japan when she was appointed Minister of Health and Welfare by Prime Minister Hayato Ikeda.^[1] She served as a minister for five months, stepping down in December 1960.

Nakayama retired from the Diet in 1969, and was succeeded in her seat by her son, Masaaki.^[4] Nakayama died of throat cancer at an Osaka hospital on October 11, 1976, aged 85.^[5]

Nakayama and her husband had two sons who also went into national politics: Representative Taro Nakayama and Representative Masaaki Nakayama. Representative Yasuhide Nakayama is her grandson and Masaaki's son.