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 O. deltoides. The majority of the 22 species of Oscularia currently recognised, however, possess toothless leaves.

Oscularia deltoides is an easy to grow mesemb succulent groundcover, ideal as an accent plant and for low maintenance and water wise gardens. Oscularia deltoides is a robust, South African endemic trailing perennial shrublet. The stems are succulent and reddish. The leaves are characteristically three-angled, sickle-shaped and grey-green, often tinged red in the drier season. This species is easily distinguished from the others as it is the only one with the leaf margins and keel prominently red-toothed. The scented flowers are mainly pink and are produced in early summer and open in the afternoons. Oscularia deltoides requires the same germination techniques as other succulents do. Seeds should be sown during autumn in winter rainfall areas.