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.