Bossiaea stephensonii grows up to 1 m high, and is mostly glabrous but sometimes the young growth has long, fine hairs.
 The stems are flat.

The leaves are alternate and  1-foliolate with the lamina being elliptic to oblong, and  10–20 mm long.
The leaf apex is pointed and recurved, and the stipules are narrow and triangular.

It flowers from August to October, with flowers that are 8–12 mm long, on  pedicels (≤ 7 mm long).
 The bracts are few, and the bracteoles are about 2.5 mm long.
 The calyx is 3–4 mm long.
The bright yellow petals with reddish markings are roughly equal and the keel is red.
The ovary is smooth and contains 6 ovules.

The pod is oblong and 15–25 mm long.
Bossiaea stephensonii grows up to 1 m high, and is mostly glabrous but sometimes the young growth has long, fine hairs.  The stems are flat. 
The leaves are alternate and  1-foliolate with the lamina being elliptic to oblong, and  10–20 mm long. The leaf apex is pointed and recurved, and the stipules are narrow and triangular.
It flowers from August to October, with flowers that are 8–12 mm long, on  pedicels (≤ 7 mm long).  The bracts are few, and the bracteoles are about 2.5 mm long.  The calyx is 3–4 mm long. The bright yellow petals with reddish markings are roughly equal and the keel is red. The ovary is smooth and contains 6 ovules. 
The pod is oblong and 15–25 mm long.
Bossiaea stephensonii