San Andrés Huayapam is a town and municipality in Oaxaca in south-western Mexico. The municipality covers an area of 14.03 km. It is part of the Centro District in the Valles Centrales region. Huayapam makes up part of the IV Federal Electoral District of Oaxaca. As of 2005, the municipality had a total population of 4,508. The municipality includes part of the Benito Juárez National Park.