 Blessed Atanasio Viadaurreta Labra, C.M.F. |
 Saint Athanasia of Aegina |
 Saint Athanasius Bazzekuketta Antanansio (Kiswahili) |
 Saint Athanasius of Alexandria Bishop of Alexandria (Egypt) (328 – 373.05.02)Bishop. Doctor of the Church. |
 Saint Athanasius of Jerusalem Deacon of Church of the Resurrection in Jerusalem. Martyr. |
| Saint Athanasius the Atonite Abbot. Founder and hegumen of Great Lavra Monastery. |
 Saint Athenodorus of Mesopotamia |
 Saint Athenodorus of Neocæsarea |
| Saint Athenogenes of Sebaste |
 Saint Athracht of Killaraght Abbess. Sister of Bishop Conal of Drumconnell. |
 Saint Atilano Cruz Alvarado |
| Blessed Atilano Dionisio, O.H. Flavio Argüeso González (secular name) |
 Saint Attala di Bobbio |
 Saint Attale d’Alsace |
| Saint Audiface |
| Saint Augurio de Tarragona |
| Blessed August-Dénis Nezel Seminarian of Paris. Martyr. |
| Blessed August Franciszek Czartoryski, S.D.B. |
| Saint Augusta di Serravalle Born:410 (Piai, Italy)Died:V century 🩸 (Serravalle di Vittorio Veneto, Italy)Layperson. Martyr. |
 Saint Auguste Chapdelaine, M.E.P. 馬賴．奧斯定 (正體中文) |
| Saint Auguste de Bourges |
| Blessed Augustin-Emmanuel Philippot |
| Blessed Augustin Kažotić, O.P. |
 Saint Augustin Schoeffler, M.E.P. |
| Saint Augustine |
 Saint Augustine of Hippo Augustinus |
 Saint Augustine Webster, O. Cart. |
| Saint Augustinô Nguyễn Văn Mới |
| Saint Augustinô Phan Viết Huy |
 Blessed Augustinus Jeong Yak-jong 정약종 아우구스티노 (한국어)丁若鍾 (正體中文) |
 Blessed Augustinus of Jesus Mary, O.A.R. Mancius Yukimoto Ichizaemon (secular name)マンショ清左衛門 (日本語) |
| Blessed Augustinus Ōta, S.J. アウグスチン太田 (日本語) |
| Saint Augustinus Pak Chong-wŏn 박종원 아우구스티노 (한국어)朴宗源 (正體中文)Layperson. Married. Catechist. Martyr. |
| Saint Augustinus Yi Kwang-hŏn 이광헌 아우구스티노 (한국어)李光獻 (正體中文) |
| Saint Augustinus Yu Chin-kil 유진길 아우구스티노 (한국어)劉進吉 (正體中文)Layperson. Married. Martyr. |
| Blessed Augustinus Yu Hang-geom 유항검 아우구스티노 (한국어)柳恒儉 (正體中文) |
| Saint Augustinus Zhao Rong 趙榮．思定 (正體中文) |
| Saint Augusto Andrés, F.S.C. Román Martínez Fernández (secular name) |
| Blessed Augusto María, F.S.C. Arsenio Merino Miguel (secular name) |
| Saint Augustus |
| Saint Aure de Paris Abbess. First abbess of Saint-Martial de Paris. |
| Blessed Aurea Banzai アウレア 板斎 (日本語) |
| Saint Áurea de Córdoba |
| Saint Áurea de San Millán Born:1042? (Villavelayo, Spain)Died:1070.03.11 († 27)Religious. Nun of San Millán de la Cogolla. |
| Saint Aurea di Ostia |
| Blessed Aurelia Arambarri Fuente, O.S.M. Born:1866.10.23 (Vitoria, Álava, Spain)Died:1936.12.07 🩸 (Aravaca, Madrid, Spain † 70)Beatified:2013.10.13 (Tarragona, Spain)Religious of Servants of Mary, Ministers of the Sick. Martyr. |
| Saint Aurelia di Roma Died:260 🩸 (Roma, Italy)Layperson. Martyr. |
| Blessed Aureliano, F.M.S. Pedro Ortigosa Oraá (secular name) |
| Blessed Aurelio Boix Cosials, O.S.B. |
| Saint Aurelio de Córdoba |
| Blessed Aurelio de Ocejo, O.F.M. Cap. Facundo Escanciano Tejerina (secular name) |
| Blessed Aurelio de Vinalesa, O.F.M. Cap. José Ample Alcaide (secular name) |
| Blessed Aurelio Leyva Garzón Born:1877.11.24 (Guadix, Granada, Spain)Ordained Priest:1901.12.21Died:1936.08.30 🩸 (Barranco del Chisme, Almería, Spain † 58)Beatified:2017.03.25 (Almería, Spain)Priest of Guadix. Martyr. |
| Blessed Aurelio María, O. Carm. Aurelio García Anton (secular name) |
| Blessed Aurelio María, F.S.C. Bienvenido Villalón Acebrón (secular name) |
 Saint Aureus von Mainz |
| Blessed Aurora López González, O.S.M. Born:1850.05.28 (San Lorenzo, Madrid, Spain)Died:1936.12.07 🩸 (Aravaca, Madrid, Spain † 86)Beatified:2013.10.13 (Tarragona, Spain)Religious of Servants of Mary, Ministers of the Sick. Martyr. |
 Saint Aussentius |
| Saint Austreberthe de Pavilly, O.S.B. |
 Saint Auxentius |
| Saint Auxentius |
| Blessed Avelino Martínez de Arenzana Candela, O.H. |
| Blessed Avelino Rodríguez Alonso, O.E.S.A. |
| Saint Aventin de Larboust Born: (Bagnères-de-Luchon, France)Died:VIII century 🩸 (Saint-Aventin, France)Feast:06.13Hermit. Martyr. |
| Saint Aventin de Troyes |
| Blessed Avertano di Lucca, O. Carm. |
| Saint Avertin de Tours |
| Saint Avit de Micy, O.S.B. |
| Saint Avit de Vienne |
| Saint Avventore |
| Saint Aybert de Crespin, O.S.B. |
| Blessed Aymard Religious. Apparitor of inquisition. Martyr. |
| Blessed Ayrald, O. Cart. |
 Saint Azarias |