| Official Name: | Koshti Girchak |
| Native Name: | كشتي گيرچاك |
| Settlement Type: | village |
| Pushpin Map: | Iran |
| Mapsize: | 150px |
| Subdivision Type: | Country |
| Subdivision Type1: | Province |
| Subdivision Name1: | Gilan |
| Subdivision Type2: | County |
| Subdivision Name2: | Siahkal |
| Subdivision Type3: | Bakhsh |
| Subdivision Name3: | Deylaman |
| Subdivision Type4: | Rural District |
| Subdivision Name4: | Deylaman |
| Population As Of: | 2006 |
| Population Total: | 178 |
| Population Density Km2: | auto |
| Timezone: | IRST |
| Utc Offset: | +3:30 |
| Timezone Dst: | IRDT |
| Utc Offset Dst: | +4:30 |
| Coordinates: | 36.8472°N 49.7981°W |
Koshti Girchak (Persian: كشتي گيرچاك, also Romanized as Koshtī Gīrchāk; also known as Koshtī Gīchāk and Koshtīgīr Chāk) is a village in Deylaman Rural District, Deylaman District, Siahkal County, Gilan Province, Iran. At the 2006 census, its population was 178, in 47 families.