J
- James, brother of Jesus
- James, son of Alphaeus
- James, son of Zebedee
- Jan Hus
- Jansenism
- Jason of Tarsus
- Jehovah's Witnesses
- Jerome
- Jesus
- Jesus in Christianity
- Jesus Justus
- Jesus movement
- Joachim
- Joanna, wife of Chuza
- Johannine epistles
- John Calvin
- John Chrysostom
- John Knox
- John Mark
- John of Cappadocia
- John of Patmos
- John Scholasticus
- John Smyth (Baptist minister)
- John the Apostle
- John the Baptist
- John the Evangelist
- John the Merciful
- John VI of Constantinople
- John Wycliffe
- John X of Constantinople
- Joseph Barsabbas
- Joseph of Arimathea
- Joses
- Jubilees
- Judas Barsabbas
- Judas Iscariot
- Judas of Galilee
- Judas the Zealot
- Jude the Apostle
- Jude, brother of Jesus
- Junia
- Junius Annaeus Gallio
- Justin Martyr