Constantine Doukas (or Doux) (died 913) is a prominent Byzantine general.

In 904, he stops the influential eunuch court official Samonas from defecting to the Arabs.

In return, Samonas manipulates his father, Andronikos Doukas, into rebelling and fleeing to the Abbasid court in 906/907.

Constantine follows his father, but soon escapes and returns to Byzantium, where he is restored by Leo VI the Wise (r. 886–912) to favor and entrusted with high military offices.

Upon the death of the Emperor Alexander (r. 912–913), Constantine, with the support of several aristocrats, unsuccessfully tries to usurp the throne from the young Constantine VII (r. 913–959), bu tis killed in a clash with supporters of the legitimate emperor.