| Official Name: | Municipality of Santa Filomena |
| Native Name: | Município de Santa Filomena |
| Subdivision Type: | Country |
| Subdivision Name: | Brazil |
| Subdivision Type1: | Region |
| Subdivision Name1: | Northeast |
| Subdivision Type2: | State |
| Subdivision Name2: | Piauí |
| Leader Title: | Mayor |
| Leader Name: | Ernani de Paiva Maia (PSDB) |
| Established Title: | Settled |
| Established Date: | 1938 |
| Area Total Km2: | 5285.447 |
| Population As Of: | 2020 [1] |
| Population Total: | 6,254 |
| Population Density Km2: | 1.2 |
| Timezone: | BRT |
| Utc Offset: | -3 |
| Coordinates: | -9.1119°N -45.9219°W |
| Blank Name: | HDI (2000) |
| Blank Info: | 0.618 – medium[2] |
Santa Filomena is the westernmost city in the Brazilian state of Piauí. The city lies near the Parnaíba River, which forms the border with the state of Maranhão.
The municipality contains part of the Uruçui-Una Ecological Station.