Tewodros II (Ge'ez: ዳግማዊ ቴዎድሮስ, baptized as Gebre Kidan; c. 1818 – 13 April 1868) was Emperor of Ethiopia from 1855 until his death in 1868. His rule is often placed as the beginning of modern Ethiopia and brought an end to the decentralized Zemene Mesafint (Era of the Princes).Tewodros II's origins were in the Era of the Princes, but his ambitions were not those of the regional nobility. He sought to re-establish a cohesive Ethiopian state and to reform its administration and church. He sought to restore Solomonic hegemony, and he considered himself the Elect of God.Tewodros II's first task after having reunited the other provinces was to bring Shewa under his control. During the Era of the Princes, Shewa was, even more than most provinces, an independent entity, its ruler even styling himself Negus (Neguece), the title for King. In the course of subduing the Shewans, Tewodros took with him a Shewan prince, Menelik II who he brought up as his own son, who would later become Emperor (or Atse) himself. Despite his success against Shewa, Tewodros faced constant rebellions by stiffnecked nobles in other regions not understanding the benefits of modernization. He ultimately committed suicide at the Battle of Magdala, during the British Expedition to Abyssinia.

In the first six years of his reign, the new ruler managed to put down these rebellions, and the empire was relatively peaceful from about 1861 to 1863, but the energy, wealth, and manpower necessary to deal with regional opposition limited the scope of Tewodros's other activities.

Tewodros II never realized his dream of restoring a strong monarchy, although he took many important initial steps. He sought to establish the principle that governors and judges must be salaried appointees. He also established a professional standing army, rather than depending on local lords to provide soldiers for his expeditions. He introduced the collection of books in the form of a library, tax codes, as well as a centralized political system with respective administrative districts. He also intended to reform the church but he was confronted by strong opposition when he tried to impose a tax on church lands to help finance government activities. His confiscation of these lands gained him enemies in the church and little support elsewhere. Essentially, Tewodros was a talented military campaigner.