Isabel Mayer was a Dominican feminist, politician and socialite from the province of Monte Cristi in the Northwest of the Dominican Republic.
She was a member of the feminist group Acción Feminista Dominicana (AFD) that helped secure suffrage for women in the Dominican Republic in 1942 under dictator Rafael Trujillo.
She served as a senator from her home province from 1942-1944 and also as governor of both Monte Cristi and Santiago.
A number of foreign journalists referred to her as a celestina, or madam, for Trujillo during the regime.