The simple leaves of Olinia ventosa are opposite, growing on thick petioles of 3 mm to 7 mm long.

The leaf-shape is obovate to oblanceolate, i.e. the broadest part usually nearer the tip than the base, while the leaf width varies. The leaf-tip tapers or is rounded, sometimes notched on mature leaves; the base tapers into the petiole. The leaf margins are entire, wavy and slightly rolled under. Leaf dimensions range from 3,5 m to 8 m in length by 2 cm to 3,5 cm in width.

Leaf surfaces are hairless and glossy dark green above, pale, dull green below. The cream coloured leaf midrib is recessed above while prominent below, the lateral veins curving in, away from the margins. The net-veining is obscure above, the veining translucent against the light (Coates Palgrave, 2002; Pooley, 1993; www.plantzafrica.com).