桑海帝国（Empire of Songhai），西非历史上的一个古老国家，15世纪至16世纪最为强大，为萨赫勒地区最后一个黑人原住民大帝国。

7世纪时桑海人在登迪创建小王国，后迁至加奥，先后臣属于加纳帝国和马里帝国，逐渐皈依伊斯兰教。15世纪后期，桑尼·阿里即位后沿尼日尔尔河大力扩张，占领马里帝国中心城市廷巴克图，正式创建桑海帝国。桑海最盛时期领土西至大西洋，东至豪萨人区域，北至摩洛哥南境。

桑尼·阿里死后国家陷入内乱，1549年登位的阿斯吉亚·达乌德曾经一度重振帝国，但他在1582年去世后，帝位继承问题令帝国再次陷入内乱。1590年，摩洛哥派遣四千人的军队入侵，1591年3月击败为数约四万人但武器落后的桑海军，占领加奥、廷巴克图等地，桑海帝国瓦解。

The Songhai Empire (also transliterated as Songhay) was a state that dominated the western Sahel in the 15th and 16th century. At its peak it was one of the largest states in African history. The state is known by its historiographical name, derived from its leading ethnic group and ruling elite, the Songhai. Sonni Ali established Gao as the capital of the empire, although a Songhai state had existed in and around Gao since the 11th century. Other important cities in the empire were Timbuktu and Djenné, conquered in 1468 and 1475 respectively, where urban-centered trade flourished. Initially, the empire was ruled by the Sonni dynasty (c.1464–1493), but it was later replaced by the Askiya dynasty (1493–1591).