Saint John or St. John usually refers to either John the Baptist or John the Apostle.

Saint John or St. John may also refer to:

• John the Baptist (c. 6 BC – c. AD 30), preacher, ascetic, and baptizer of Jesus Christ
• John the Evangelist (c. AD 6 – c. 100), presumed author of the Fourth Gospel, traditionally identified with John the Apostle
• John of Patmos, author of the Book of Revelation, traditionally identified with John the Apostle and the Evangelist
• John the Wonderworking Unmercenary (died c. 304), Egyptian or Mesopotamian healer
• John Chrysostom (c. 347 – 407), Antiochene Archbishop of Constantinople
• John Cassian (360–435), probably Scythia-Minor priest and abbot
• John and Paul (died 362), Roman martyrs
• John of Egypt (died 394), Egyptian hermit
• John the Silent (452–558), Bishop of Taxara
• Pope John I (470–526), Italian pope
• John of Ephesus (507–586), Syrian ecclesiastical historian
• John Climacus (579–649), Syrian or Byzantine monk and abbot
• John Scholasticus (died 577), 32nd Patriarch of Constantinople
• Patriarch John IV of Constantinople (died 595), also known as John the Faster, first Ecumenical Patriarch
• John the Merciful (died c. 610), Cyprian Patriarch of Alexandria
• John I Agnus ('the Lamb', 7th century), 25th bishop of Tongres
• John III of the Sedre (died 648), Syriac Orthodox Patriarch of Antioch
• John of Damascus (676–749), Syrian monk and priest, also known as John Damascene
• John of Beverley (died 721), Angle bishop
• John of Pavia (died 813), Bishop of Pavia
• John of Rila (876–946), Bulgarian priest and hermit
• John Gualbert (died 1073), Founder of the Vallumbrosan Order
• John Theristus (1049–1129), Italian Benedictine monk
• John of Pulsano (1070–1139), or Giovanni di Matera, Italian abbot
• John of Tufara (1084–1170), Italian monastery founder
• John of the Grating (1098–1168), Bishop of Aleth
• John of Matha (1160–1213), French priest; founder of the Trinitarian Order
• John of Meda (1100–1159), Italian priest
• John Kukuzelis (1280–1360), Byzantine Orthodox Christian composer, singer and reformer
• John of Nepomuk (1340–1393), Bohemian vicar general of Jan of Jenštejn
• John of Capistrano (1386–1456), Italian friar, summoner of European troops for the 1456 siege of Belgrade
• John Cantius (1390–1473), Polish priest and theologian
• John of Sahagún (1419–1479), Spanish priest
• John Fisher (c. 1469 – 1535), English cardinal and martyr
• Juan Diego (1474–1548), first Native-American saint
• John Houghton (martyr) (1486–1535), English abbot and martyr (one of the Forty Martyrs of England and Wales)
• John Stone (martyr) (died 1539), English friar and martyr (one of the Forty Martyrs of England and Wales)
• John of God (1495–1550), Portuguese friar; founder of the Brothers Hospitallers of St. John of God
• John of Ávila (1500–1569), Spanish Jewish converso priest, missionary and mystic
• John Payne (martyr) (1532–1582), English priest and martyr (one of the Forty Martyrs of England and Wales)
• John de Ribera (1532–1611), or Juan de Ribera, Bishop of Valencia
• John Leonardi (1541–1609), Italian priest; founder of the Clerks Regular of the Mother of God of Lucca
• John of the Cross (1542–1591), Spanish Jewish converso friar, priest and mystic; joint founder of the Discalced Carmelites
• John Boste (1544–1594), English priest and martyr (one of the Forty Martyrs of England and Wales)
• John Rigby (martyr) (died 1600), English martyr (one of the Forty Martyrs of England and Wales)
• John Roberts (martyr) (c. 1577 – 1610), Welsh priest, Prior of Saint Gregory'sone of the Forty Martyrs of England and Wales
• John Sarkander (1576–1620), Polish priest and martyr
• John Ogilvie (saint) (1579–1615), Scottish priest and martyr
• John Jones (martyr) (died 1598), Welsh priest and martyr (one of the Forty Martyrs of England and Wales)
• John Macias (1585–1645), Spanish missionary
• John Southworth (martyr) (1592–1654), English priest and martyr (one of the Forty Martyrs of England and Wales)
• Jean de Brébeuf (1593–1649), French missionary and martyr (one of the North American Martyrs)
• John Francis Regis (1597–1640), French priest
• Jean de Lalande (died 1646), French missionary and martyr (one of the North American Martyrs)
• John Berchmans (1599–1621), Flemish seminarian
• John Kemble (martyr) (1599–1679), English priest and martyr (one of the Forty Martyrs of England and Wales)
• John Eudes (1601–1680), or Jean Eudes, French priest and founder of the Congregation of Jesus and Mary
• John Wall (priest and martyr) (1620–1679), English priest and martyr (one of the Forty Martyrs of England and Wales)
• John Plessington (c. 1637 – 1679), English priest and martyrone of the Forty Martyrs of England and Wales
• Saint John Lloyd (died 1679), Welsh priest and martyr (one of the Forty Martyrs of England and Wales)
• John de Britto (1647–1693), Portuguese missionary and martyr
• John of Tobolsk (1651–1715), Metropolitan of Tobolsk
• Jean-Baptiste de La Salle (1651–1719), French priest; founder of the Institute of the Brothers of the Christian Schools
• John Joseph of the Cross (1654–1739), Ischian friar, priest and Vicar Provincial of the Alcantarine Reform in Italy
• John Dat (c. 1765–1798), Vietnamese priest and martyr
• Jean Vianney (1786–1859), French priest
• John Hoan Trinh Doan (c. 1789/1798–1861), Vietnamese priest and martyr
• John Thanh Van Dinh (1796–1840), Vietnamese martyr
• John Baptist Y (1800–1839), one of the Korean Martyrs
• John Henry Newman (1801–1890), English Oratorian priest, convert from Anglicanism
• John Gabriel Perboyre (1802–1840), or Jean-Gabriel Perboyre, French missionary and martyr
• John Baptist Con (1805–1840), Vietnamese martyr
• John Charles Cornay (1809–1837), or Jean-Charles Cornay, French missionary and martyr
• John Neumann (1811–1860), Bohemian missionary, Bishop of Philadelphia, founder of the first American Catholic diocesan school system
• John Bosco (1815–1888), Italian priest and educator; founder of the Salesians of Don Bosco and the Salesian Cooperators
• John of Kronstadt (1829–1909), Russian archpriest and synod member
• John of Shanghai and San Francisco (1896–1966), also known as John the Wonderworker, Archbishop of Shanghai and San Francisco
• Pope John XXIII (1881–1963), Italian pope from 1958 to 1963
• Pope John Paul II (1920–2005), Polish pope from 1978 to 2005

• St John (name), a list of people and fictional characters with the given name or surname

• Saint John (electoral district), New Brunswick
• Saint John, New Brunswick, a port city on the Bay of Fundy
• Saint John River (Bay of Fundy), a river flowing through Saint John, New Brunswick
• Roman Catholic Diocese of Saint John, New Brunswick, a suffragan of the Archdiocese of Moncton

• Saints John, Colorado, also known as Saint John, a former mining town
• St. John, Florida
• St. John, Indiana
• Saint John, Warrick County, Indiana
• St. John, Kansas
• Saint John, Kentucky
• Saint John Plantation, Maine
• Saint John River (Bay of Fundy), from northern Maine into Canada
• St. John, Missouri
• St. John, Pulaski County, Missouri
• St. John, North Dakota
• St. John, Utah, Rush Valley, Utah
• Saint John, Austin, Texas, a neighborhood
• St. John, Washington
• St. John, Wisconsin
• Saint John, U.S. Virgin Islands, an island in the Caribbean Sea
• Saint John, Saint Croix, U.S. Virgin Islands, a small town on Saint Croix
• St. John Township (disambiguation)

• Saint John Parish, Antigua and Barbuda, a parish on the island of Antigua
• Saint John Parish, Barbados
• Saint John Parish, Dominica
• Saint John Parish, Grenada
• Saint John, Jersey, a parish of Jersey in the Channel Islands
• Saint John, Malacca, original name of the Portuguese settlement in Malaysia
• St John, Cornwall, England

• St John Ambulance, a foundation established by the Order of St. John
• Order of Saint John (chartered 1888), a royal order of chivalry established in 1831
• St. John (clothing), a luxury American fashion brand
• St. John (crater), an eroded lunar impact crater on the Moon's far side
• St. John (restaurant), Smithfield, London
• St. John Publications, a defunct American magazine and Golden Age comic book publisher
• "St. John", a song by Aerosmith from Permanent Vacation (Aerosmith album), 1987

• All pages with titles containing St John
• All pages with titles containing Saint John
• Saint Jhn, American musician
• John the Divine (disambiguation)
• Saint John Cemetery (disambiguation)
• Saint John's (disambiguation)
• St. John the Baptist (disambiguation)
• Agios Ioannis (disambiguation) (Greek)
• Saint Juan (disambiguation) (Spanish)
• Saint-Jean (disambiguation) (French)
• San Giovanni (disambiguation) (Italian)
• San Juan (disambiguation) (Spanish)
• Sankt Johann (disambiguation) (German)
• Sant Joan (disambiguation) (Catalan)
• São João (disambiguation) (Portuguese)
• Sveti Ivan (disambiguation) (Croatian)