Santiago Jamiltepec is a town located in the Mexican state of Oaxaca. It serves as the seat of the surrounding municipality of the same name.
The town is situated in the Jamiltepec District within the western portion of the Costa Chica Region. Geographically, it lies 30 km east of Pinotepa Nacional along Federal Highway 200 and approximately 460 km southwest of the state capital, Oaxaca de Juárez.