| Official Name: | Kumkapı |
| Image Alt: | Seafood restaurants in Kumkapı at night |
| Mapsize: | 250px |
| Map Alt: | Location of Fatih in Istanbul |
| Subdivision Type: | Country |
| Subdivision Name: |  Turkey |
| Subdivision Type1: | Province |
| Subdivision Name1: | Istanbul |
| Subdivision Type2: | District |
| Subdivision Name2: | Fatih |
| Timezone: | GMT +2 |
| Area Code: | (+90) 212 |
Kumkapı (meaning "sand gate" in Turkish) is a quarter in Fatih district of Istanbul. It is located along the northern shore of Marmara Sea. Up to recent times, Kumkapı is the center of the Armenian community of the city, boasting a school and several churches. It is also where the seat of the Armenian Patriarchate of Constantinople is located. The quarter is famous for its many fish restaurants; therefore attracting many local and foreign tourists round the year.
In the Byzantine period, the area was known in Greek as Kontoskàlion.
Kumkapı used to be served by a station on the Sirkeci suburban until 2013, when the station was indefinitely closed as a part of the Marmaray project. The Kumkapı station is now served by the T6 line inaugurated in February 2024. Kumkapı is also easily accessible by sea.