Domitian (; Latin: Domitianus; 24 October 51 – 18 September 96) was a Roman emperor who reigned from 81 to 96. The son of Vespasian and the younger brother of Titus, his two predecessors on the throne, he was the last member of the Flavian dynasty. Described as "a ruthless but efficient autocrat", his authoritarian style of ruling put him at sharp odds with the Senate, whose powers he drastically curtailed.

Domitian had a minor and largely ceremonial role during the reigns of his father and brother. After the death of his brother, Domitian was declared emperor by the Praetorian Guard. His 15-year reign was the longest since that of Tiberius. As emperor, Domitian strengthened the economy by revaluing the Roman coinage, expanded the border defenses of the empire, and initiated a massive building program to restore the damaged city of Rome. Significant wars were fought in Britain, where his general Agricola attempted to conquer Caledonia (Scotland), and in Dacia, where Domitian was unable to procure a decisive victory against King Decebalus. Domitian's government exhibited strong authoritarian characteristics. Religious, military, and cultural propaganda fostered a cult of personality, and by nominating himself perpetual censor, he sought to control public and private morals.

As a consequence, Domitian was popular with the people and army, but considered a tyrant by members of the Roman Senate. Domitian's reign came to an end in 96 when he was assassinated by court officials. He was succeeded the same day by his advisor Nerva. After his death, Domitian's memory was condemned to oblivion by the Senate, while senatorial and equestrian authors such as Tacitus, Pliny the Younger, and Suetonius propagated the view of Domitian as a cruel and paranoid tyrant. Modern revisionists instead have characterized Domitian as a ruthless but efficient autocrat whose cultural, economic, and political programs provided the foundation of the peaceful second century.