Muñiz is a town in San Miguel Partido, within Buenos Aires Province, Argentina. It lies in the urban conurbation of Greater Buenos Aires, the metropolitan area that surrounds the country's capital city.
As part of Greater Buenos Aires, Muñiz forms one of the many localities that make up the densely settled ring around the autonomous city of Buenos Aires. Administratively it belongs to San Miguel Partido, one of the partidos, or districts, into which Buenos Aires Province is divided.