Engin was born in the Greek town of Komotini () to Faik Engin, a well-known parliamentarian in the late '40s and one of the three ethnic Turkish members of the Greek parliament between 1946-1950. Oktay Engin became one of the few ethnic Turkish students to graduate from Greek gymnasiums in those years. Turkish officials encouraged him to study law, offering him a scholarship, so that he could promote the interests of Turkish citizens in Greece. He thus entered Aristotle University of Thessaloniki in 1953. When he was in his second year, he was accused of incitement in the bombing incident. Engin said that he had been followed by Greek intelligence agents so closely from the start of his university education, that he could name one ("Triondafilos").