| Official Name: | Ardajin |
| Native Name: | اردجين |
| Settlement Type: | village |
| Pushpin Map: | Iran |
| Mapsize: | 150px |
| Subdivision Type: | Country |
| Subdivision Type1: | Province |
| Subdivision Name1: | Zanjan |
| Subdivision Type2: | County |
| Subdivision Name2: | Khorramdarreh |
| Subdivision Type3: | Bakhsh |
| Subdivision Name3: | Central |
| Subdivision Type4: | Rural District |
| Subdivision Name4: | Khorramdarreh |
| Population As Of: | 2006 |
| Population Total: | 1,177 |
| Population Density Km2: | auto |
| Timezone: | IRST |
| Utc Offset: | +3:30 |
| Timezone Dst: | IRDT |
| Utc Offset Dst: | +4:30 |
| Coordinates: | 36.2217°N 49.0156°W |
Ardajin (Persian: اردجين, also Romanized as Ardajīn and Ardjīn; also known as Ardahīn and Ardin) is a village in Khorramdarreh Rural District, in the Central District of Khorramdarreh County, Zanjan Province, Iran. At the 2006 census, its population was 1,177, in 286 families.