San Ildefonso Amatlán is a town and municipality in Oaxaca in south-western Mexico.

The municipality covers an area of 91.9 km².

It is part of the Miahuatlán District in the south of the Sierra Sur Region.

As of 2005, the municipality had a total population of 2,009.

[1] This article about a location in the Mexican state of Oaxaca is a stub.