Aetios or Aetius () was a Byzantine eunuch official and one of the most trusted advisers of Byzantine empress Irene of Athens (r. 797–802). After Irene's rise to sole rule, Aetios developed an intense rivalry with her eunuch chief minister Staurakios. After Staurakios's death, Aetios became the leading man in the state. He plotted to usurp the throne for his brother, Leo, but lost power when Irene was deposed in 802.