- Damasus, Pope
- Damian (and Cosmas), Martyrs
- Daria and Chrysanthus, Martyrs
- Dedication of the Basilicas of Saint Peter and Saint Paul
- Dedication of the Lateran Basilica, the Church of the Most Holy Saviour, Rome
- Delphinus, Bishop of Bordeaux
- Departed, Commemoration of the Faithful Departed, All Souls Day
- Didace Pelletier, Confessor
- Didacus or Diego, Franciscan Confessor
- Dionysius the Areopagite, Bishop, and his Companions, Martyrs
- Dionysia, Peter, Andrew and Paul Martyrs
- Dominic de Guzman, Founder of the Dominican Order
- Dominic Savio, Confessor
- Dominic of Silos, Abbot
- Donatian and Rogatian, Martyrs
- Dormition of Mary, Mother of Christ
- Dorothy, Virgin and Martyr