St. - Subu
- St. Abban of Magheranoidhe
- St. Abban of New Ross
- St. Abban the Hermit
- St. Abbon
- St. Acacius
- St. Acca
- St. Adalard
- St. Adalbert
- St. Adamnan (Eunan)
- St. Adelaide
- St. Adeodatus
- St. Ado of Vienne
- St. Adrian III
- St. Adrian of Canterbury
- St. Aedan of Ferns
- St. Aelred
- St. Aengus (The Culdee)
- St. Afra
- St. Agapetus I
- St. Agatha
- St. Agatho
- St. Agilulfus
- St. Agnes of Assisi
- St. Agnes of Bohemia
- St. Agnes of Montepulciano
- St. Agnes of Rome
- St. Agricius
- St. Aidan of Lindisfarne
- St. Ailbe
- St. Aileran
- St. Alban
- St. Albert
- St. Albertus Magnus
- St. Alcmund
- St. Aldhelm
- St. Aldric
- St. Alexander (of Alexandria)
- St. Alexander (Of Cappadocia and Jerusalem)
- St. Alexander (Of Comana)
- St. Alexander I