Dukes | Titles by Rank
- Dukes of Portsmouth
- Dukes of Poznan
- Dukes of Praslin
- Dukes of Presenzano
- Dukes of Presenzano
- Dukes of Prim
- Dukes of Primo de Rivera
- Dukes of Prússia
- Dukes of Queensberry
- Dukes of Rambouillet
- Dukes of Ratibor
- Dukes of Ratzeburg
- Dukes of Raudnitz
- Dukes of Rauzan Duras
- Dukes of Regla
- Dukes of Reichstadt
- Dukes of Reitano
- Dukes of Rethel
- Dukes of Retz
- Dukes of Riánsares
- Dukes of Richelieu
- Dukes of Richmond
- Dukes of Richmond
- Dukes of Richmond (I)
- Dukes of Richmond e Somerset
- Dukes of Rignano
- Dukes of Ripalda
- Dukes of Rivas
- Dukes of Rivoli
- Dukes of Rocca Mondragone
- Dukes of Roccapiomonte
- Dukes of Rohan
- Dukes of Rohan-Chabot
- Dukes of Roquelaure
- Dukes of Ross
- Dukes of Rothes
- Dukes of Rothesay
- Dukes of Roxburghe
- Dukes of Rubi
- Dukes of Ruffec
- Dukes of Ruffo
- Dukes of Rutland
- Dukes of Sabbioneta
- Dukes of Sabiote
- Dukes of Sabran
- Dukes of Sagan
- Dukes of Saint Albans
- Dukes of Saint-Simon
- Dukes of Salandra
- Dukes of Saldanha