Oscularia is a genus of succulent flowering plants in the family Aizoaceae, native to semi-arid and rocky habitats in the Western Cape of South Africa. It was previously included within the related genus Lampranthus, but was split off as a separate genus, due to differences in its fruit and flower. The species are restricted to the Western Cape Province, South Africa, where they occur only in winter rainfall areas. Their habitat is typically rocky areas of sandstone. Osculum means small mouth in Latin. Oscularia therefore means a group of small mouths and refers to the toothed leaves of Oscularia deltoides. The majority of the 22 species of Oscularia currently recognised, however, possess toothless leaves.

Oscularia prasina, previously known as Lampranthus prasinus, is a South African endemic species found in the Western Cape province. During winter it produces an abundance of striking silky bright purple flowers which attract butterflies to the garden.