| Official Name: | Kui Sadaf |
| Native Name: | كوئ صدف |
| Settlement Type: | village |
| Pushpin Map: | Iran |
| Mapsize: | 150px |
| Subdivision Type: | Country |
| Subdivision Type1: | Province |
| Subdivision Name1: | Golestan |
| Subdivision Type2: | County |
| Subdivision Name2: | Gorgan |
| Subdivision Type3: | Bakhsh |
| Subdivision Name3: | Central |
| Subdivision Type4: | Rural District |
| Subdivision Name4: | Estarabad-e Jonubi |
| Population As Of: | 2006 |
| Population Total: | 1,712 |
| Population Density Km2: | auto |
| Timezone: | IRST |
| Utc Offset: | +3:30 |
| Coordinates: | 36.8483°N 54.5086°W |
Kui Sadaf (Persian: كوئ صدف, also Romanized as Kūi Sadaf; also known as Qazzāq Maḩalleh) is a village in Estarabad-e Jonubi Rural District, in the Central District of Gorgan County, Golestan Province, Iran. At the 2006 census, its population was 1,712, in 336 families.
The village is located just east of Gorgan's city limits.[1]