| Type: | parish |
| Official Name: | São Marcos da Ataboeira |
| Region: | Alentejo |
| Cim: | Baixo Alentejo |
| District: | Beja |
| Municipality: | Castro Verde |
| Coordinates: | 37.708°N -7.941°W |
| Area Total: | 104.13 |
| Population As Of: | 2011 |
| Population Total: | 338 |
São Marcos da Ataboeira is a Portuguese town/parish in the municipality of Castro Verde. The population in 2011 was 338,[1] in an area of 104.13 km2.[2] The village was integrated into the municipality of Castro Verde during the nineteenth century, and is situated 13 km north east from the municipal seat.
It is a territory where the pseudo-steppe is predominant, and grazing has an important role in preserving the traditional landscape. The area of the parish belongs to the SPA - Special Protection Area, for endangered species of steppe birds such as the great bustard and lesser kestrel. The SPA makes part of the Natura 2000 project of the European Union.
A few kilometres from the nearby town of Salto sits the chapel of 'Our Lady of Aracelis', a place of pilgrimage and festivities during the first weekend of September.