Otholobium dreweae is an upright shrublet assigned to the Pea family of about 15 cm (5.9 in) high, that appears after the vegetation burned down from the underground rootstock and forms mat-like clumps of hardly branching, leafy stems.

The stems are set with stiff, entire, alternate leaves with a single leaflet and heads consisting of 12-18 initially dark pink, later white, pea-like flowers with a white nectar guide on a peduncle as long as the leaves at the end of the stem.

Its erect, distinctly ridged and scarcely branching, densely leafy stems are up to 15 cm (5.9 in) long.

[1] As in most Faboideae, the corolla is zygomorph, forms a specialized structure and consists of 5 free, initially dark pink petals that later fade to white.

[1] Otholobium dreweae can be distinguished from O. thomii that is a semi-erect or decumbent (not erect) plant with initially densely hairy (not sparsely hairy), pliable (not stiff) leaves, that each have at their base 2 softly hairy, broadly oval lance-shaped stipules with a pointy tip (not hairless and awl-shaped), each triplet of flowers is subtended by a lance-shaped bract that is shed quickly (not egg-shaped and persistent), and its petals are light to deep purple in colour (not dark pink that fades to white).

O. lanceolatum and O. rotundifolium are woody shrublets with cylindrical stems covered with dot-like glands and distantly set leaves (not densely leafy with ridged, herbaceous stems without dots), with pale mauve or white petals (not light to deep purple).

O. zeyheri in which the leaves that are higher on the stems have 3 leaflets (not all leaves with just one leaflet), carries spikes that consist of 25-30 sets of 3 flowers, on a stalk that is 4-5 times longer than the subtending leaf (not 3-9 triplets on an inflorescence stalk just 1-2 times longer).

Here it forms dense clumps growing in full sun on bands of shale in a vegetation type called mountain fynbos.