Saint Leontius may refer to:
Christian Saints
- Leontius of Byzantium (485–543), monk who wrote treatises on christology
- Leontius of Rostov (c. 1016-c. 1072), Russian monk and bishop
- Leontius of Monemvasia (1377-1452), 15th-century Greek monk
- Leontius Stasievich (1884-1972), archimandrite in the Russian Orthodox Church
Bishops
- Leontius of Autun, bishop of Autun, died c. 430 AD
- Leontius of Caesarea (died 337), bishop of Caesarea, AD
- Leontius of Fréjus (died 488), bishop of Fréjus, died 5th century
- Leontius of Saintes, bishop of Saintes, 7th century
- Leontius of Camerino, bishop of Camerino, martyred ~250 AD
- Leontius the Elder, died c. 541, bishop of Bordeaux
Martyrs
- Leontius, Hypatius and Theodulus, died 70-79 AD
- Leontius of Tsarevo, Russian bishop killed in 1917
- Leontius of Vanand, one of the Leontine martyrs of Persia, killed in 455 AD
- Leontius of Constantinople, (with Martyrs Julian, Marcian, John, James, Alexius, Demetrius, Photius, Peter, and Mary, 730, (August 9, Eastern Orthodox liturgics)