Gretchen Marie Hau is a Puerto Rican politician and lawyer.

She is a representative, affiliated to the Popular Democratic Party of Puerto Rico.

Hau studied at Colegio Radians in Cayey, Graduated from the University of Puerto Rico at Cayey with a bachelor's degree in Business Administration and a master's degree in Business Administration with concentration in Human Resources and Personnel Administration from the Interamerican University of Puerto Rico.

She is the first woman to hold the position of executive director of the Puerto Rico Mayors Association for four years from 2015 to 2019.

In 2023 she resigned in the Puerto Rico Senate and went to the Puerto Rico House of Representatives for the 29th district after the death of Representative José Aníbal Díaz.