Tewodros II (also known as Theodore II) (born Kassa Hailu) (1818-1868) was an emperor of Ethiopia.

He was born into a country rife with civil war, and he destroyed many provincial warlords before becoming emperor. He sought to unify and modernise Ethiopia, however, since he was nearly always away on campaign during his tenure as emperor, disloyal leaders frequently tried to dislodge him whilst he was away fighting.

He moved the capital city of the Empire from Gondar, first to Debre Tabor, and later to Magdala. Tewodros ended the division of Ethiopia among the various regional warlords and princes that had vied among each other for power for almost two centuries. He forcibly re-incorporated the regions of Gojjam, Shewa and Wollo under the direct administration of the Imperial throne after having been ruled by local branches of the Imperial dynasty (in Gojjam and Shewa) or other warlords (Wollo).

During the period that Tewodros was emperor of Ethiopia, the Red Sea region was marked by constant warfare. The Ottoman Empire and Egypt in the north were both ardent enemies of Ethiopia, and on numerous occasions sought to take over the country.

Tewodros, fearful of these northerly powers, wrote a letter to Queen Victoria asking for British assistance in the region. After two years had passed and Tewodros had not received a reply, he imprisoned several British subjects in an attempt to get Victoria's attention. This led to a British invasion under Robert Napier, who, with the help of several of the warlords that Tewodros spent his life fighting against, defeated the Ethiopian army. As a result, Tewodros committed suicide on April 13, 1868.

Soon after his suicide, the British looted and burned the city of Magdala including its churches, and departed from Ethiopia. They took a large number of treasures that today can be seen in various museums and libraries in Europe, as well as private collections.