| Luncoiu | |
| Pushpin Map: | Romania |
| Subdivision Type1: | Country |
| Subdivision Name1: | Romania |
| Subdivision Type2: | Counties |
| Subdivision Name2: | Hunedoara County |
| Subdivision Type3: | Villages |
| Subdivision Name3: | Luncoiu de Sus, Luncoiu de Jos, Brad |
| Length: | 11km (07miles) |
| Source1: | Bihor Mountains |
| Mouth: | Crișul Alb |
| Mouth Coordinates: | 46.1295°N 22.794°W |
| Basin Size: | 67km2 |
| Tributaries Left: | Valea Lungă |
| Tributaries Right: | Ruda |
The Luncoiu is a left tributary of the river Crișul Alb in Romania. It discharges into the Crișul Alb in Brad. Its length is 11km (07miles) and its basin size is 67km2.