| Aín | |
| Settlement Type: | Municipality |
| Pushpin Map: | Spain |
| Pushpin Map Caption: | Location in Spain |
| Subdivision Type: | Country |
| Subdivision Name: |  Spain |
| Subdivision Type1: | Autonomous community |
| Subdivision Type2: | Province |
| Subdivision Name2: | Castelló |
| Subdivision Type3: | Comarca |
| Subdivision Name3: | Plana Baixa |
| Subdivision Type4: | Judicial district |
| Subdivision Name4: | Nules |
| Coordinates: | 39.8836°N -0.3408°W |
| Elevation M: | 498 |
| Area Total Km2: | 12.30 |
| Population Demonym: | Aïnencs |
| Population Density Km2: | auto |
| Blank Name Sec1: | Official language(s) |
| Blank Info Sec1: | Valencian and Spanish |
| Timezone: | CET |
| Utc Offset: | +1 |
| Timezone Dst: | CEST |
| Utc Offset Dst: | +2 |
| Postal Code Type: | Postal code |
| Postal Code: | 12530 |
| Area Code Type: | Dialing code |
| Leader Title: | Mayor |
| Leader Name: | Ricardo Miro Ballester |
| Blank Name Sec2: | Climate |
Aín (Spanish: Ahín) is a town in eastern Spain, in the province of Castellón, part of the autonomous community of Valencia.
It is home to a 13th-century castle.