Dukes | Titles by Rank
- Dukes of Almenara Alta
- Dukes of Almodovar del Campo
- Dukes of Almodovar del Rio
- Dukes of Almodovar del Valle
- Dukes of Alsácia
- Dukes of Alta Bavaria
- Dukes of Alta Lorena
- Dukes of Amalfi-E
- Dukes of Amalfi-I
- Dukes of Ancaster and Kesteven
- Dukes of Ancenis
- Dukes of Ancona
- Dukes of Andria-E
- Dukes of Andria-I [Balzo]
- Dukes of Andria-I [Carafa]
- Dukes of Angoulême
- Dukes of Anhalt
- Dukes of Anhalt-Bernburg
- Dukes of Anjou
- Dukes of Ansola
- Dukes of Antin
- Dukes of Antioquia
- Dukes of Anville
- Dukes of Aosta
- Dukes of Apezteguía
- Dukes of Apice
- Dukes of Apulia
- Dukes of Aquara
- Dukes of Aquitaine
- Dukes of Aragvi
- Dukes of Arce
- Dukes of Archirafi
- Dukes of Arco
- Dukes of Arcos
- Dukes of Arenberg
- Dukes of Arenella
- Dukes of Arévalo del Rey
- Dukes of Argyll
- Dukes of Arión
- Dukes of Arjona
- Dukes of Arpajon
- Dukes of Arschot
- Dukes of Ascoli
- Dukes of Athens
- Dukes of Atholl
- Dukes of Atri
- Dukes of Atripalda
- Dukes of Atrisco
- Dukes of Aubigny
- Dukes of Audiffret-Pasquier