Regina Ongsiako Reyes-Mandanas (July 3, 1964 – May 5, 2022) was a Filipina politician who served as the Representative of Marinduque's lone district from 2013 to 2016.

A consistent Dean's Lister,[citation needed] she finished her Foreign Service degree at Georgetown University.

She was a devoted member of the Special Projects Group of Gawad Kalinga and was engaged in supporting rehabilitation centers for abused and neglected children, disaster management and relief operations, and volunteer recruitment.

She was proclaimed as the winner by the Marinduque COMELEC Provincial Board of Canvassers and subsequently took her oath of office before President Benigno S. Aquino III and House Speaker Feliciano Belmonte in Malacañang as the duly elected representative of the Lone District of Marinduque.

She was also a member of several committees, which include the committees on Appropriations, Justice, Health, Natural Resources, Veterans Affairs and Welfare, Suffrage and Electoral Reforms, Youth and Sports Development, Higher and Technical Education, Overseas Workers Affairs, Public Order and Safety, and Women and Gender Equality.