Constantine Harmenopoulos (Greek: Κωνσταντῖνος Ἁρμενόπουλος; 1320 – c. 1385) was a Byzantine jurist from Greece who held the post of katholikos kritēs ("universal judge") of Thessalonica, one of the highest judicial offices in the Byzantine Empire.

He is best known for his Hexabiblos (1344–1345), a law book in six volumes in which he compiles a wide range of Byzantine legal sources. First printed 1540 in Paris, the Hexabiblos was widely adopted in the Balkans under the Ottoman Empire. In 1828, it was also adopted as the interim civil code in the newly independent Greek state.