Mary Yamashiro Otani (Japanese: メアリー山城大谷Mearī Yamashiro Ōtani) (July 5, 1923 in Berkeley, California – August 22, 2005) was a Richmond, California community activist. She was a student at UC Berkeley when she was forcibly removed to an internment center for Japanese Americans, first living with her family at the Tanforan Racetrack in San Bruno and later at an isolated desert camp in Topaz, Utah. Later a Quaker group persuaded the authorities to allow college-age students to continue their studies at East Coast schools. Yamashiro then attend Boston University where she met her husband Bill.
She was the summary writer for city elections voter guides. Yamashiro set up the Richmond Farmers Market and the Richmond Annex Senior Center. She oversaw the Richmond City Council and the Ports Commission for the League of Women Voters. She was a Unitarian Universalist. She was one of six siblings born to an immigrant Okinawan family and, because of this, established a YWCA college fund for poor first-time college students of Southeast Asian descent.