Theodosia of Constantinople was an eighth-century Christian nun and martyr living in the Byzantine Empire. Born in Constantinople, she was raised in the Monastery of Holy Martyr Anastasia after the death of her parents. She is primarily remembered for her courageous resistance against the iconoclastic movement, specifically during the reign of Emperor Leo III. Her actions during the removal of a religious icon led to her arrest and subsequent execution, establishing her as a significant figure in the history of Byzantine icon veneration.