- James the Greater, Apostle
- James the Less (and Philip), Apostles
- James of The March of Ancona, Franciscan Priest
- James, Bishop of Nisibis and Doctor of the Syrian Church
- Jane Frances de Chantal, Foundress
- Jane of Valois, Queen
- Januarius, Bishop of Beneventum, Martyr
- Japan, The Holy Martyrs of Japan
- Jean de la Lande (one of the Holy North American Martyrs
- Jeanne Leber, Recluse
- Jerome, Doctor of the Church
- Jerome Emiliani, Founder of the Somascans
- Jesus: Baptism of Our Lord
- Jesus: Circumcision of Our Lord
- Jesus: Epiphany of Our Lord
- Jesus: Exaltation of the Holy Cross
- Jesus: Nativity of Our Lord
- Most Precious Blood of Jesus
- Jesus: Presentation in the Temple or Candlemas
- Jesus: Feast of the Holy Redeemer
- Jesus: Transfiguration of Our Lord
- Joachim, Father of the Most Blessed Virgin Mary
- Joan of Arc, Virgin, Martyr
- Joan Antide Thouret, Foundress
- John the Almsgiver, Patriarch of Alexandria
- John, Apostle, Evangelist, and Prophet
- John (Apostle) before the Latin Gate
- John the Baptist, Prophet, (Feast of his Nativity)
- John the Baptist, (Feast of the Beheading)
- John Baptist de LaSalle, Founder
- John and Paul, Martyrs
- John Berchmans, Jesuit Seminarian
- John Bosco, Founder
- John de Brebeuf (one of the Holy North American Martyrs
- John de Britto, Martyr
- John Buonagiunta, one of the Seven Holy Servite Founders
- John Cantius, Priest
- John Capistran, Confessor
- John Chrysostom, Bishop of Constantinople, Doctor of the Church
- John Climacus, Abbot
- John of the Cross, Doctor of the Church
- John Damascene, Doctor of the Church
- John the Discalced, Franciscan Friar
- John Eudes, Founder
- John Francis Regis, Jesuit missionary
- John Gabriel Perboyre, Lazarist Priest and Martyr
- John of God, Founder
- John Gualbert, Founder
- John Joseph of the Cross, Confessor, priest, Franciscan Friar
- John of Matha, Founder
- John Nepomucene
- John of Sahagun or St. Fagondez, Confessor, Augustinian
- John the Silent, Bishop, Monk of Saint Sabas
- John Vianney, Curé of Ars, Confessor
- Jonas and Barachisius, and their Companions, Martyrs
- Josaphat, Archbishop and Martyr
- Joseph, Spouse of the Blessed Virgin, Virginal Father of Jesus and Patron of the Universal Church
- Joseph the Worker
- Joseph Benedict Cottolengo, Founder
- Joseph Calasanctius, Founder of the Clerks Regular of Religious Schools
- Joseph of Cupertino, Franciscan Priest
- Jovita (and Faustinus), Martyrs
- Jude (and Simon), Apostles and Martyrs
- Julia, Virgin, Martyr, Patron of Corsica
- Julian, Martyr, and Basilissa
- Juliana Falconieri, Virgin
- Juliana of Mt. Cornillon, Virgin
- Julitta and her son Cyricus, Martyrs
- Julius I, Pope
- Justina (and Cyprian), Martyrs
