| Siamanna | |
| Official Name: | Comune di Siamanna |
| Pushpin Map: | Italy Sardinia |
| Coordinates: | 39.9167°N 54°W |
| Region: | Sardinia |
| Province: | Oristano (OR) |
| Frazioni: | Pranixeddu |
| Mayor: | Franco Vellio Melas |
| Area Total Km2: | 28.36 |
| Population Footnotes: | [1] |
| Population Total: | 811 |
| Population As Of: | 28 February 2017 |
| Population Demonym: | Siamannesi |
| Elevation M: | 100 |
| Postal Code: | 09080 |
| Area Code: | 0783 |
Siamanna is a comune (municipality) in the Province of Oristano in the Italian region Sardinia, located about 80km (50miles) northwest of Cagliari and about 15km (09miles) east of Oristano.
Siamanna borders the following municipalities: Allai, Oristano, Ruinas, Siapiccia, Simaxis, Villaurbana.