María Odilia Castro Hidalgo (1908–1999) was a Costa Rican teacher, communist and feminist. She founded the parent organization which would become the National Association of Educators. Exiled for her communist activities after the Costa Rican Civil War, Castro later returned and founded several social welfare programs. She taught for 32 years and served as a nurse in Costa Rica and Venezuela. Castro was admitted to the Costa Rican National Institute for Women (INAMU)'s Gallery of Women in 2006.