| Ierul Îngust | |
| Pushpin Map: | Romania |
| Subdivision Type1: | Country |
| Subdivision Name1: | Romania |
| Subdivision Type2: | Counties |
| Subdivision Name2: | Bihor County |
| Length: | 12km (07miles) |
| Mouth: | Ier |
| Mouth Location: | Upstream of the Romanian-Hungarian border |
| Mouth Coordinates: | 47.2962°N 21.8899°W |
| Basin Size: | 43km2 |
| Custom Label: | River code |
| Custom Data: | III.1.44.33.28.11 |
The Ierul Îngust is a right tributary of the river Ier in Romania. It flows into the Ier near Diosig, close to the Hungarian border. Its length is 12km (07miles) and its basin size is 43km2.