Olinia ventosa is an evergreen forest tree of between 10-20 m in height. In optimal conditions it is found as a large, shapely, many branched, leafy tree with a spreading crown, but when growing on an exposed hillside it is a medium-sized tree or large shrub. In older trees the trunk is often fluted and gnarled. The bark is thin, greyish and smooth on young trees, but as the tree begins to age, it becomes very rough and scaly with an ochre to reddish tinge.

The leaves are ovate to elliptic, 35-80 x 18-35 mm, glossy dark green above and pale green below, margin entire, occurring in opposite pairs. Young twigs display a distinctive four-angled pattern. Crushed leaves, twigs, bark and freshly cut wood all smell strongly of almonds.

The tiny white to pale pink flowers are borne in dense axillary clusters of up to 60 mm long and are faintly sweet-scented. The tree is very attractive when in flower, as the flowers stand out very well against the glossy dark green leaves. The flowers appear in spring, from August to October.

The berry-like fruits are coral pink to bright red when ripe with a distinctive, round scar at the tip; about 10 mm in diameter. The fruits have a hard, woody centre containing several small seeds. According to Palmer & Pitman (1961), Olinia ventosa does not bear fruit regularly, sometimes only once every 5-7 years.