| Dacius, Martyr |
| Dagmar Margaret of Bohemia, Queen of Denmark |
| Dagobert II, King of Austrasia, Martyr |
| Dalmatius of Constantinople, Archimandrite |
| Dalmatius, Bishop of Pavia |
| Dalmatius. Bishop of Rodez |
| Damasus, Pope |
| Damian DeVeuster of Molokai, Priest, Pastor of Lepers |
| Damian, Bishop of Pavia |
| Damian, Physician and Martyr |
| Daniel |
| Daniel Comboni, Bishop, Founder of the Comboni Missionaries of the Heart of Jesus |
| Daniel of Moscow, Prince, Monk, Founder of the Danilov Monastery |
| Daniel the Stylite, Priest and Confessor |
| Daniel, Abbot of Skete, Egypt |
| Daniel, Martyr |
| Daphrosa (Dafrosa), Mother of St. Bibiana, Martyr |
| Daria, Greek, martyred in Rome with her Egyptian husband, Chrysanthus |
| Dario Acosta Zurita. Priest, Cristero Martyr |
| Dathus, Bishop of Ravenna |
| David (Dewi), Bishop of Menevia (St. Davids), Patron of Wales |
| David Galvan Bermudez, Mexican Priest, Cristero Martyr |
| David Lewis, Welsh Jesuit Priest, Martyr |
| David of Thessalonica, Hermit |
| David Roldan Lara, Mexican Layman, Cristero Martyr |
| David Uribe Velasco, Mexican Priest, Cristero Martyr |
| David, Abbot of Himmerode |
| Davinus the Pilgrim |
| Deicola (Deicuil), Irish Missionary Abbot |
| Deiniol (Daniel), First Bishop of Bagor, Carnarvon, Wales |
| Delphine, Mother St. Delphine (Marie-Antoinette) Fontbonne, Canadian nun |
| Delphinus, Bishop of Bordeaux |
| Demetria of Rome, Virgin and Martyr |
| Demetrius of Sirmium (and Thessaloniki), Deacon and Martyr |
| Denis (Dionysius), First Bishop of Paris and Martyr |
| Denis Auguste Affre, Archbishop of Paris, martyred for peace, June 27. 1848 |
| Dentilius |
| Deodata, Martyr |
| Deodatus of Sora, Martyr |
| Deodatus, Bishop of Nevers |
| Deodatus, bishop of Nola |
| Deogratias, Bishop of Carthage |
| Desiderius (Didier), Bishop of Langres, Martyr |
| Desiderius (Didier), Bishop of Vienne |
| Désiré-Félicien-François-Joseph, Cardinal Mercier, Archbishop of Mechlin-Brussels |
| Deusdedit (Adeodatus I), Pope |
| Deusdedit (Frithona, Adeodatus), First Anglo-Saxon Archbishop of Canterbury |
| Devota (Devote), Virgin and Martyr, Patroness of Monaco |
| Diana de Andelo, Dominican Prioress of St. Agnes Convent in Bologna |
| Dictino, Bishop of Astorga |
| Didacus (San Diego) of Alcala, Franciscan Brother |
| Diego Jose of Cadiz, Capuchin Preacher to the Andalusia area |
| Diego Luis of San Vitores, Jesuit Missionary to Guam, died with St. Pedro Calungsod |
| Digna of Augsburg, Virgin and Martyr |
| Digna of Cordoba, Martyr |
| Dignus, Martyr |
| Dilectus, Martyr |
| Dimitry (Daniil Saavich Tuptalo/Tuptalenko), Bishop of Rostov, Composet |
| Dimitry of Priluckji, Russian Monk |
| Diodora, Martyr |
| Diodoros, Bishop of Tarsus |
| Diodorus |
| Diomedes of Nicaea, Martyr |
| Dionysius of Aquileia, Lay Person, Martyr |
| Dionysius of Kiev, Russian monk |
| Dionysius of Zakynthos, Archbishop of Aegina |
| Dionysius the Areopagite, Disciple of St. Paul, First Bishop of Athens, Martyr |
| Dionysius, Bishop of Corinth |
| Dionysius, Bishop of Vienne |
| Dionysius, Patriarch of Alexandria |
| Dionysius, Pope and Martyr |
| Dioscorus I, Patriarch of Alexandria |
| Dioscorus, Martyr |
| Disciola of Poitiers, Nun in Holy Cross Convent |
| Dismas (Dimas), the “Good Thief” |
| Dius the Wonderworker, Antiochene Abbot, then an Archimadrite in Constantinople |
| Dodolinus (Dodolin). Bishop of Vienne |
| Dogmael of Wales, 6th century Hermit |
| Domenica del Paradiso, Florentine Dominican Prioress |
| Domincianus |
| Dominic de Guzman, Priest and Founder of the Order of Preachers, Dominicans |
| Dominic de la Calzada, Hermit, built bridge, hospital, and hotel on the Camino de Santiago |
| Dominic Henares, Dominican Bishop and Martyr of Tonkin, China |
| Dominic of the Holy Rosary (Ioannes Nagata Magoshichiro) Dominican Martyr of Nagasaki |
| Dominic of the Mother of God Barberi, Passionist Priest |
| Dominic Savio |
| Dominica, Martyr |
| Dominican Martyrs of Tonkin, China |
| Domininus, Hermit near Tulle, France |
| Domitian |
| Domitilla (Flavia Domitilla), great-niece of Emperors Domitian, Titus, and the Senator, St. Flavius Clemens, Martyr |
| Domnolus, Bishop of Le Mans |
| Donatus, (Donagh the Irishman), Bishop of Fiesole |
| Donatus, Bishop of Arezzo, Martyr |
| Donatus, Martyr |
| Donatus, Martyr |
| Donatus, Martyr |
| Donnan, Irish Abbot of Eigg, Missionary to the Picts |
| Dorotheus of Gaza, Abbot |
| Dorotheus, Bishop of Tyre |
| Dorothy of Cappadocia, Virgin and Martyr |
| Dorothy of Montau, Widow and Mystic |
| Dositheus, Monk |
| Droctoveus, Cenobite, near Paris |
| Drosis (Droside) of Persia, Martyr |
| Drosis, Martyr |
| Dubhthach, Bishop of Ross, Scotland |
| Dubritius (Dyfryg, Devereaux) Bishop in Wales |
| Dula of Nicomedia, Virgin and Martyr |
| Dulcidius, Bishop of Agen |
| Dunstan, Archbishop of Canterbury |
| Dymphna, Virgin and Martyr |
