| Tirso Tirsu | |
| Source1 Location: | Punta Pianedda (Buddusò) plateau |
| Mouth: | Mediterranean Sea |
| Mouth Location: | Gulf of Oristano |
| Mouth Coordinates: | 39.885°N 8.5406°W |
| Subdivision Type1: | Country |
| Subdivision Name1: | Italy |
| Length: | 152km (94miles) |
| Source1 Elevation: | 985m (3,232feet) |
| Mouth Elevation: | 0m (00feet) |
| Discharge1 Avg: | 4.28m3/s |
| Basin Size: | 3375km2 |
The Tirso (Sardinian: Tirsu, Latin Thyrsus) is a 152km (94miles) river, the most important of the island of Sardinia (Italy). It rises from the plateau of Buddusò, on the slopes of the Punta Pianedda at an elevation of 985m (3,232feet) and crosses the island from east to west, passing through Lake Omodeo and entering the sea in the Gulf of Oristano.