Hae Mo-su () was the founder of Buyeo. According to the Samguk sagi, Hae Mo-su was the father of Goguryeo's founder, Ko Chumong () also known as Dongmyeong of Goguryeo. According to the Samguk yusa, Hae Mo-su was the son of heaven, riding in a chariot of five dragons, to establish Bukbuyeo (Northern Buyeo).
According to legend, Chumong is the child of Hae Mo-su and Yuhwa, daughter of Habaek, the Goguryeo god of the Amnok River or according to an alternative interpretation, the sun god Haebalk ().
Hae Mo-su does not appear in older Chinese records or on the Gwanggaeto Stele that describes the founding of Goguryeo. It is thought that Goguryeo integrated the founding legend of Buyeo after the former conquered the latter.