Iosif Ispovednik was a 9th-century Byzantine archbishop and the brother of Theodore Stoudites. Born to Photios and Theoktiste, he initially lived an ascetic life at the Sakkoudion monastery. During his tenure as the Archbishop of Thessalonica, he became a prominent defender of icon veneration and opposed the illegal marriage of Emperor Constantine VI. Due to his religious convictions, he faced imprisonment and torture under the reign of Leo V before being released by Michael II.