Alexios V Doukas (died December 1204), Latinized as Alexius V Ducas, was Byzantine emperor from February to April 1204, just prior to the sack of Constantinople by the participants of the Fourth Crusade.

John III Doukas Vatatzes, Latinized as Ducas Vatatzes (Iōannēs III Doukas Vatatzēs, c. 1192 – 3 November 1254), was Emperor of Nicaea from 1221 to 1254.

Constantine X Doukas or Ducas (Kōnstantinos Doukas, – 23 May 1067), was Byzantine emperor from 1059 to 1067.

Michael VII Doukas or Ducas, nicknamed Parapinakes (a reference to the devaluation of the Byzantine currency under his rule), was the senior Byzantine emperor from 1071 to 1078.

The Byzantine Empire was ruled by emperors of the Doukas dynasty between 1059 and 1081.

(Theodōros Komnēnos Doukas, Latinized as Theodore Comnenus Ducas, died 1253) the ruler of Epirus and Thessaly from 1215 to 1230 and of Thessalonica and most of Macedonia and western Thrace from 1224 to 1230.