汉萨同盟（拉丁语：Hansa、Hansa Teutonica或Liga Hanseatica，英语：Hanseatic League，又译汉撒同盟和汉莎同盟），12-13世纪中欧的神圣罗马帝国与条顿骑士团诸城市之间形成的商业、政治联盟，以德意志北部城市为主。汉萨（Hansa、或Hanse ）一词，德文意为“公所”或者“会馆”，最早是指从须德海到芬兰、瑞典到挪威的一群商人与一群贸易船只。12世纪中期逐渐形成，14世纪晚期—15世纪早期达到鼎盛，加盟城市最多达到160个。1367年成立以吕贝克城为首的领导机构，有汉堡、科隆、不来梅等大城市的富商、贵族参加。拥有武装和金库。1370年战胜丹麦，订立《施特拉尔松德条约》。同盟垄断波罗的海地区贸易，并在西起伦敦，东至诺夫哥罗德的沿海地区创建商站，实力雄厚。15世纪中叶后，随着英、俄、尼德兰等国工商业的发展和新航路的开辟，转衰，1669年解体。现今德国的国家航空公司汉莎航空（Lufthansa）即是以汉萨同盟命名的。

The Hanseatic League (also known as the Hanse or Hansa; Low German:Hanse, Dudesche Hanse, Latin:Hansa, Hansa Teutonica or Liga Hanseatica) was a commercial and defensive confederation of merchant guilds and their market towns. It dominated Baltic maritime trade (c. 1400–1800) along the coast of Northern Europe. It stretched from the Baltic to the North Sea and inland during the Late Middle Ages and early modern period (c. 15th to 19th centuries). A Hanse, later spelled as Hansa, was the middle low German word for a convoy, and this word was applied to bands of merchants traveling between the Hanseatic cities whether by land or by sea.