December 1
editAdelgar; Agericus of Verdun; Airy of Verdun; Algeric of Verdun; Edmund Campion; Saint Eligius; Simon of Cyrene;
December 2
editAbibon; Adamnan of Coldingham; Adrias & Paulina; Chromatius; John of Ruysbroeck;
December 3
editAbbo of Auxerre; Pope Abraham of Alexandria; Abran; Agapius, Seleucus and Mamas; Agricola; Francis Xavier;
December 4
editAda; Adrechildis; Anno II, Archbishop of Cologne; John of Damascus; Saint Osmund; Peter Chrysologus;
December 5
editSaint Abercius; Birinus; Sabbas the Sanctified;
December 6
editAbraham of Kratia; Agatha; Saint Nicholas;
December 7
editAgatho; Ambrose; Pope Eutychian; Martyrs of Africa;
December 8
editFeast of the Immaculate Conception; Martyrs of Africa;
December 9
editAbibus of Samosata; Abracius; Abrax; Aemilianus; Aggai of Edessa; Aprax; Feast of the Immaculate Conception; Peter Fourier;
December 10
editAbundius; Pope Leo I;
December 11
editAemilianus; Pope Damasus I; Daniel the Stylite; Pope Miltiades;
December 12
editAbra of Poitiers; Apra; Odile; Our Lady of Guadalupe; Vicelinus;
December 13
editDecember 14
editAbraham the Great of Kidunja; Abundius; Agnellus of Naples;
December 15
editAdelheidis; Mary di Rosa;
December 16
editAdelaide; Aggaeus; Agricola; Haggai; Martyrs of Africa;
December 17
editShadrach, Meshach, and Abednego; Agatho;
December 18
editAdjutor; Afra; Frumentius;
December 19
editAdjutor; Adjutor; Adjutus of Portesan; Ajut; Pope Anastasius I; Ignatius of Antioch;
December 20
editAbraham of Armenia; Ignatius of Antioch;
December 21
editAddaeus; Thomas the Apostle;
December 22
editAbban of New Ross; Ago of Poitiers; Alexander of Cappadocia and Jerusalem; Saint Chrysogonus;
December 23
editAbassad; Agathopus;
December 24
editAchaicus; Achmed; Adela;
December 25
editAdalsindis; Martyrs of Achmin; Martyrs of Panopolis;
December 26
editAbadiu of Antinoe; Saint Stephen; Vincentia Lopez; Pope Zosimus;
December 27
editSaint Fabiola; John, Apostle and Evangelist;
December 28
editAbel; Massacre of the Innocents;
December 29
editAchatius; Adhanius & Astea; Aesculapius; Massacre of the Innocents; Peter the Venerable; Thomas Becket;
December 30
editAbraham the Writer; Commemoration of St. Mary the Virgin; Pope Dionysius;
December 31
editAggaeus; Pope Sylvester I;