| Trịnh Khải 鄭楷 | |
| Trịnh lords Lord of Tonkin | |
| Father: | Trịnh Sâm |
| Mother: | Dương Thị Ngọc Hoan |
| Spouse: | ? |
| Birth Date: | 10 October 1763 |
| Birth Place: | Đông Kinh, North Vietnam |
| Death Date: | 23 July 1786 |
| Death Place: | Đông Kinh, North Vietnam |
| Regnal Name: | Đoan Nam Vương (端南王) |
| Full Name: | Trịnh Tông (鄭棕) Trịnh Khải (鄭楷) |
| Succession: | Trịnh Lords |
| Reign: | 1782–1786 |
| Predecessor: | Trịnh Cán |
| Successor: | Trịnh Bồng |
| House: | Trịnh Lords |
| Religion: | Buddhism |
Đoan Nam Vương Trịnh Khải (chữ Hán: 鄭楷, 10 October 1763 – 23 July 1786) was one of the Trịnh lords in northern Vietnam.[1] He fought against the armies of the infant Trịnh Cán to win leadership of the northern warlords (reigning 29 November 1782 – July 1786), but was himself defeated by the Tây Sơn rebel leader, later emperor Nguyễn Huệ. Trịnh Khải later committed suicide while were arrested by the Tây Sơn troops.[2] He was succeeded by the last of the lords, Trịnh Bồng.