Jamno [ˈjamnɔ] is a lake in northern Poland (in West Pomeranian Voivodeship), close to the Baltic Sea. It is divided from the sea by a spit, on which lie the resorts of Mielno and Unieście.
Jamno covers an area of over 22 square kilometres (8.5 sq mi); its maximum length is 10.1 kilometres (6.3 mi) and its maximum breadth is 3.4 kilometres (2.1 mi). Its greatest depth is 3.9 metres (13 ft). The lake is popularly used for sailing.