Theodore Gabras (Greek: Θεόδωρος Γαβρᾶς) was a Byzantine governor in the Pontus who was involved in a minor unsuccessful rebellion against the Emperor Alexios I Komnenos around the year 1091. Theodore Gabras is an Eastern Orthodox martyr whose feast day is celebrated on October 2.
Theodore originally hailed from the Theme of Chaldia, and spent most of his adult life serving in the Byzantine army. A violent and energetic man, he had gained considerable fame as a gifted soldier, both courageous and cunning, with an outstanding record of success. It was reported that he rarely failed in any military task, and invariably got the better of his enemies. Already by 1067, when he commissioned a gospel preserved in St Petersburg, he had risen to the ranks of patrikios, topoteretes and hypatos. His crowning glory was the recapture of Trebizond from the Seljuk Turks during the 1080s, which he ruled for a time as if it were his own personal fiefdom.
By the late 1080s, Theodore was once again residing at Constantinople, where Alexios I was keeping a concerned eye on him. In order to avoid any unnecessary temptations, he formally appointed Theodore Dux of Trebizond and ordered him to take up his post. Leaving his eldest son Gregory at the court with the sebastokrator Isaac Komnenos, to whose daughter Gregory was engaged, he returned to Trebizond.