Tags: Monarch.
John Doukas (or Ducas) (Greek: Ιωάννης Δούκας Iōannēs Doukas) (died c. 1088) was the son of Andronikos Doukas a Paphlagonian nobleman who may have served as governor of the theme of Moesia and younger brother of Emperor Constantine X Doukas. John Doukas was the paternal grandfather of Irene Doukaina wife of Emperor Alexios I Komnenos.