Viscounts | Titles by Rank
- Viscounts of Sérgio de Sousa
- Viscounts of Serpa Pinto
- Viscounts of Serra da Tourega
- Viscounts of Serra do Pilar
- Viscounts of Serra Largo
- Viscounts of Serrado
- Viscounts of Serro Alegre
- Viscounts of Serro Azul
- Viscounts of Serro Formoso
- Viscounts of Serro Frio
- Viscounts of Setúbal
- Viscounts of Sierra
- Viscounts of Sieuve de Menezes
- Viscounts of Silho
- Viscounts of Silva
- Viscounts of Silva Andrade
- Viscounts of Silva Carvalho
- Viscounts of Silva Cota
- Viscounts of Silva Figueira
- Viscounts of Silva Loio
- Viscounts of Silva Melo
- Viscounts of Silva Monteiro
- Viscounts of Silva Viana
- Viscounts of Silvares
- Viscounts of Silveira
- Viscounts of Silves
- Viscounts of Simard de Pitray
- Viscounts of Sinde
- Viscounts of Sistelo
- Viscounts of Sisteron
- Viscounts of Soares Franco
- Viscounts of Sobral
- Viscounts of Sobreira
- Viscounts of Socorro
- Viscounts of Solages
- Viscounts of Somzée
- Viscounts of Sorraia
- Viscounts of Sotomaior
- Viscounts of Soulan
- Viscounts of Soultrait
- Viscounts of Sourches
- Viscounts of Sousa Carvalho
- Viscounts of Sousa da Fonseca
- Viscounts of Sousa Fontes
- Viscounts of Sousa Franco
- Viscounts of Sousa Prego
- Viscounts of Sousa Rego
- Viscounts of Sousa Soares
- Viscounts of Sousel
- Viscounts of Sousela