St. Leo may refer to one of several saints named Leo, including:

• Leo of Patara (died c. 260), early Christian martyr
• Leo of Montefeltro (died 366), bishop of Montefeltro
• Pope Leo I the Great (died 461), Pope of Rome
• Emperor Leo I the Great (died 474), Eastern Roman Emperor
• Leo of Cappadocia (died c. 580)
• Pope Leo II (died 683), Pope of Rome
• Leo of Catania (died c. 785), Wonderworker and bishop of Catania in Sicily
• Leo of Bayonne  [ it ], France (died c. 890), feast day March 1

Eastern Orthodox

• Leo of Optina (1768–1841), hieroschemamonk and elder of Optina Monastery
• Lev Egorov (1889–1937), archimandrite and hieromartyr

Roman Catholic

• Pope Leo III (died 816), Pope of Rome
• Pope Leo IV (died 855), Pope of Rome
• Pope Leo IX (died 1054), Pope of Rome

Index of articles associated with the same name

This set index article includes a list of related items that share the same name (or similar names).