Rhesaina (Rhesaena) (Ancient Greek: Ρέσαινα and Ρεσαίνα)[1] or Resina (Ῥέσινα)[2] was a city in the late Roman province of Mesopotamia Secunda and a bishopric that was a suffragan of Dara.

[3] Rhesaina (Rhesaena, Resaena – numerous variations of the name appear in ancient authors) was an important town at the northern extremity of Mesopotamia, near the sources of the Chaboras (now the Khabur River.

Hierocles (Synecdemus, 714, 3) also locates it in this province but under the name of Theodosiopolis (Θεοδοσιούπολις); it had in fact obtained the favour of Theodosius the Great and taken his name.

The Diocese of Rhesaina is today a suppressed and titular see of the Roman Catholic Church in the episcopal province of Mesopotamia Le Quien[4] mentions nine bishops of Rhesaena: The see is again mentioned in the 10th century in a Greek Notitia episcopatuum of the Patriarchate of Antioch (Vailhé, in "Échos d'Orient", X, 94).

Le Quien (ibid., 1329 and 1513) mentions two Jacobite bishops: Scalita, author of a hymn and of homilies, and Theodosius (1035).