Constantine VI (Ancient Greek: Κωνσταντῖνος Ϛ΄, Kōnstantinos VI) was Byzantine Emperor from 780 to 797.
Constantine VI was the only child of Emperor Leo IV and Irene. Constantine was crowned co-emperor by his father in 776, and succeeded as sole emperor in 780, at the age of nine. Due to his minority, Irene and her chief minister Staurakios exercised the regency for him. After a conspiracy against Irene was suppressed in the spring of 790 she attempted to get official recognition as empress. This backfired and with military support Constantine finally came to actual power in 790, after the Armeniacs rebelled against Irene. Nevertheless, she was allowed to keep the title of Empress, which was confirmed in 792.
On 19 April 797 Constantine was captured, blinded, and imprisoned by the supporters of his mother, who had organized a conspiracy, leaving Irene to be crowned as first Empress regnant of Constantinople. It is unknown when exactly Constantine died; it was certainly before 805, but he very likely died of his wounds shortly after being blinded. He was buried in the Monastery of St. Euphrosyne, which Irene had founded.