Santiago Tapextla is a town and municipality in Oaxaca in southeastern Mexico and is the westernmost municipality in Oaxaca.

The municipality covers an area of 128.8 km².

It is located in the Jamiltepec District in the west of the Costa Region.

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

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