| San Martín Itunyoso | |
| Settlement Type: | Municipality and town |
| Language: | Triqui |
| Pushpin Map: | Mexico |
| Pushpin Label Position: | above |
| Pushpin Map Caption: | Location in Mexico |
| Subdivision Type: | Country |
| Subdivision Name: |  Mexico |
| Subdivision Type1: | State |
| Subdivision Name1: | Oaxaca |
| Government Type: | Usos y Costumbres http://www.narconews.com/Issue40/article1603.html(Customs and Traditions) |
| Leader Title: | Municipal president |
| Leader Name: | Emilio Martínez López |
| Established Date: | 2008-2010 |
| Area Total Km2: | 82.93 |
| Population As Of: | 2005 |
| Population Total: | 2554 |
| Timezone: | Central Standard Time |
| Utc Offset: | -6 |
| Timezone Dst: | Central Daylight Time |
| Utc Offset Dst: | -5 |
| Coordinates: | 17.2333°N -150°W |
San Martín Itunyoso is a Trique language town and municipality in Oaxaca in south-western Mexico. The municipality covers an area of 82.93 km2. It is part of the Tlaxiaco District in the south of the Mixteca Region.
As of 2005, the municipality had a total population of 2,554.[1]