Nicholas Adontz (Armenian: Նիկողայոս Ադոնց, Nikoġayos Adonc’, also spelled Adonts; Portuguese: Nicolas Adontz; Russian: Николай Адонц; January 10, 1871 – January 27, 1942) was an Armenian historian, specialist of Byzantine and Armenian studies, and philologist. Adontz was the author of the Armenia in the Period of Justinian, a highly influential work and landmark study on the social and political structures of early Medieval Armenia.