Celastrina lavendularis, the plain hedge blue, is a small butterfly found in Sri Lanka, India, and Indomalayan realm that belongs to the lycaenids or blues family.

"Male. Upperside dark lavender-blue, with an extremely narrow black outer marginal border. Female paler, and of a purple lavender-blue. Forewing with the base of the costa and an outer band black. Hindwing with black anterior border and marginal row of prominent pale-bordered black spots. Cilia white, with inner black border. Underside greyish-white. Forewing with dusky-black streak at end of the cell, a discal series of oblique spots, and marginal row of small spots enclosed by a dentated line. Hindwing with three black subbasal spots, some specimens with a smaller spot at base of subcostal and another at base of lower median vein, a curved series of seven discal spots, and a marginal row of spots enclosed by a dentate line." - Frederic Moore

The butterfly was earlier known as Lycaenopsis lavendularis Moore.

It is found in Sri Lanka, India and Yunnan.