| Official Name: | Ain |
| Native Name: | آیین |
| Settlement Type: | village |
| Pushpin Map: | Iran |
| Mapsize: | 150px |
| Subdivision Type: | Country |
| Subdivision Type1: | Province |
| Subdivision Name1: | Qazvin |
| Subdivision Type2: | County |
| Subdivision Name2: | Qazvin |
| Subdivision Type3: | Bakhsh |
| Subdivision Name3: | Rudbar-e Alamut |
| Subdivision Type4: | Rural District |
| Subdivision Name4: | Moallem Kalayeh |
| Population As Of: | 2006 |
| Population Total: | 13 |
| Population Density Km2: | auto |
| Timezone: | IRST |
| Utc Offset: | +3:30 |
| Timezone Dst: | IRDT |
| Utc Offset Dst: | +4:30 |
| Coordinates: | 36.4617°N 50.4075°W |
Ain (Persian: آیین, also Romanized as Ā'īn) is a village in Moallem Kalayeh Rural District, Rudbar-e Alamut District, Qazvin County, Qazvin Province, Iran. At the 2006 census, the village population comprised 13 residents, in 4 households.