Constantine II^[1] (Armenian: Կոստանդին Բ), also Kostandin II,^{[citation needed]} (unknown^{[citation needed]} – after February 17, 1129^{[citation needed]}) was the fourth lord of Armenian Cilicia^[2] (1129^{[citation needed]}/1130^[1]).

The Chronique Rimée de la Petite Arménie (“The Rhymed Chronicle of Armenia Minor”) of Vahram of Edessa records that he was the son of Thoros I, lord of Armenian Cilicia.^{[citation needed]} His mother's name is not known.^{[citation needed]}

He died a few months after his father's death in the course of a palace intrigue.^[1] Vahram of Edessa, the historian tells us that he was cast into prison and poisoned to death.^[2]

After the death of Thoros, his only son and heir was cast into prison by some wicked people, who administered to him a poisonous drug, thus the principality came to Leon, the brother of Thoros (…).

— Vahram of Edessa: The Rhymed Chronicle of Armenia Minor^[3]

Other historians (e.g., Jacob G. Ghazarian, Vahan M. Kurkjian) suggest that Thoros I died without a male heir^[2] and was succeeded by Leon I.^[4]

• Ghazarian, Jacob G: The Armenian Kingdom in Cilicia during the Crusades: The Integration of Cilician Armenians with the Latins (1080–1393); RoutledgeCurzon (Taylor & Francis Group), 2000, Abingdon; ISBN 0-7007-1418-9
• Runciman, Steven (1952). A History of the Crusades, Volume II: The Kingdom of Jerusalem and the Frankish East. Cambridge: Cambridge University Press.

• The Barony of Cilician Armenia (Kurkjian's History of Armenia, Ch. 27)