Alexios III Angelos (Medieval Greek: Ἀλέξιος Ἄγγελος; c. 1153 – 1211), Latinized as Alexius III Angelus, was Byzantine Emperor from March 1195 to 17/18 July 1203.^[2] He reigned under the name Alexios Komnenos (Ἀλέξιος Κομνηνός) associating himself with the Komnenos dynasty (from which he was descended cognatically).

A member of the extended imperial family, Alexios came to the throne after deposing, blinding and imprisoning his younger brother Isaac II Angelos. The most significant event of his reign was the attack of the Fourth Crusade on Constantinople in 1203, on behalf of Alexios IV Angelos.