Barleria ameliae is a branched perennial herb or subshrub 0.2-1.2 m high. The leaves are elliptic to lanceolate with the upper half tapering to a sharp pointed apex (tip) and the lower half tapering to a long or short petiole (leaf stalk). Spines are present in the leaf axils (the angle between the stem and the leaf stalk or a branch).

The flowers are pale yellow to orange, arranged in a loose or fairly dense terminal spike with the lower flowers solitary in the axils of the leaves, in late summer to autumn. The corolla (petals of the flower) is 2-lipped. The upper lip is 4-lobed and the lower lip entire. The lower leaves in the inflorescence are more or less like the normal leaves and the upper leaves are usually much smaller. The bracteoles (small leaf-like structures at the base of the flower) taper to an acute apex.

It has a single seed capsule bearing two seeds. When the seed is ripe the fruit capsule explodes to distribute the seeds in different directions.