Bardas (died April 21, 866) is a Byzantine noble and high-ranking minister.

As the brother of Empress Theodora, he rises to high office under Theophilos (r. 829–842).

Although sidelined after Theophilos's death by Theodora and Theoktistos, in 855 he enginees Theoktistos's murder and becomes the de facto regent for his nephew, Michael III (r. 842–867).

Rising to the rank of Caesar, he is the effective ruler of the Byzantine Empire for ten years, a period which sees military success, renewed diplomatic and missionary activity, and an intellectual revival that heralds the Macedonian Renaissance.

He is assassinated in 866 at the instigation of Michael III's new favorite, Basil the Macedonian, who a year later will usurp the throne for himself and install his own dynasty on the Byzantine throne.