- ASCAP
- Ashkenazy, Vladimir
- Ashley, Robert
- Astaire, Fred
- Asymmetry
- Athematic, Athematic Composition
- Atkins, Chet
- Atonality
- Aubade
- Auber, Daniel-François-Esprit
- Aucassin et Nicolette
- Audiences
- Audition
- Auer, Leopold
- Aufstieg und Fall der Stadt Mahagonny
- Augmentation
- Augmented Interval
- Auld Lang Syne
- Aulos
- Auric, Georges
- Aus Italien
- Authentic Mode(s)
- Autoharp
- Automatic Composition
- Avant-Garde
- Ave Maria
- Ax, Emanuel
- Ayre
- Aznavour
