The - Thom
- The Abbey of Abingdon
- The Abbey of Ampleforth
- The Abbey of Athelney
- The Abbey of Bonne-Esperance
- The Abbey of Bursfeld
- The Abbey of Bury St. Edmund's
- The Aberdeen Breviary
- The Abomination of Desolation
- The Absolute
- The Acacians
- The Albright Brethren
- The Alexandrian Library
- The Alexandrine Liturgy
- The American College at Louvain
- The American College at Rome
- The American Protective Association
- The Anchor (as Symbol)
- The Angelicals
- The Anglo-Saxon Church
- The Annunciation of the Blessed Virgin Mary
- The Apostleship of Prayer
- The Apostolic Fathers
- The Apostolic See
- The Apostolic Union of Secular Priests
- The Archdiocese of Acerenza
- The Archdiocese of Adelaide
- The Archdiocese of Aquila
- The Ass (in Caricature of Christians)
- The Athanasian Creed
- The Augustinus-Verein
- The Authorized Version
- The Avesta
- The Bahama Islands
- The Barber Family
- The Benedictine Order
- The Benedictus
- The Bernardines
- The Bible
- The Biblical Commission
- The Black Fast
