San Juan Achiutla is a town and municipality located in the state of Oaxaca in south-western Mexico. The municipality encompasses an area of 49.76 km2 and is situated within a mountain range bounded by the hills of Negro to the east, Yucuquise to the northwest, Cuate to the north, and Totolote to the south.
The region features a temperate climate and is crossed by the Los Sabinos river, which includes the Cahuayande dam. Geographically, San Juan Achiutla is part of the Mixteca Alta, one of three regions that comprise the larger Mixteca area. The municipality is also noted for being part of what was historically known as Achiutla, a significant Prehispanic site.