The opposite leaves of Carissa bispinosa are broadly to narrowly ovate, tapering to pointed or rounded tips. The leaf base is rounded, square or lobed on petioles of up to 3 mm long. The leaf texture is leathery and hairless, the surface glossy dark green above, paler below. The yellowish midrib is prominent on the lower surface of the leaf, the lateral veins inconspicuous. Leaf margins are entire and rolled under. Leaf size varies from 1 cm to 7 cm long and 1 cm to 3,5 cm wide.
Hard, intimidating spines arm the stems among the leaves. They are opposite, once to twice forked, occasionally simple and up to 4,5 cm long. Spine shape and size vary somewhat across the distribution of the plant in nature (Coates Palgrave, 2002; Van Wyk and Van Wyk, 1997; Pooley, 1993).