Thomasia paniculata is a spreading shrub that typically grows to high and wide, its new growth densely covered with star-shaped hairs. The leaves are heart-shaped to narrowly egg-shaped, long and wide on a petiole long with rounded to wing-like stipules at the base of the petioles. The edges of the leaves are regularly notched and both sides are covered with scattered star-shaped hairs. The flowers are up to in diameter and arranged in racemes of 3 to 8 on a peduncle up to long. Each flower is on a pedicel long with densely hairy, linear bracts and similar bracteoles long at the base. The sepals are pinkish-mauve, densely covered with star-shaped hairs and joined for about half their length. Flowering occurs from September to December or from January to March.