Polyommatus (Plebicula) sagratrox, the Sierra de la Sagra blue, is a species of butterfly in the family Lycaenidae.

It is endemic to Spain in the south-east of the Iberian Peninsula.

Adults are on wing from July (normally) to August.

The host plant for the larvae is Anthyllis vulneraria microcephala, an endemic plant from the north-east Andalusia region of south-eastern Spain.