Silene longicilia is a species of flowering plant of the family Caryophyllaceae. It is endemic to Portugal.
The species is endemic to west central Portugal and it ranges from Figueira da Foz and Coimbra in the north, to Sesimbra and a part of Alentejo in the south, and has its greatest extent in limestone soils at Serras de Aire e Candeeiros, Serra de Montejunto, Serra De Sintra and an isolated population in Serra da Arrábida.[1][3] It is commonly found in rock crevices from sea-level up to 650 metres (2,130 ft) in altitude.[1]