Solanum quadriloculatum commonly known as tomato bush or wild tomato, is a flowering plant in the family Solanaceae. It is an upright perennial with hairy, grey-green thick leaves and purple flowers and grows on mainland Australia with the exception of Victoria.

Solanum quadriloculatum is an upright or spreading shrub to 0.5 m (1 ft 8 in) high, leaves thick, grey-green or yellowish-green, densely covered in star-shaped hairs, occasionally rough, prickly, elliptic to oval-shaped, 5–9 cm (2.0–3.5 in) long, 1.5–5 cm (0.59–1.97 in) wide, margins entire or slightly wavy on a petiole 1–4 cm (0.39–1.57 in) long. The purple flowers are borne in groups of 2-3, 2–2.5 cm (0.79–0.98 in) wide, 5 lobed, 4–6 mm (0.16–0.24 in) long, mostly star-shaped and peduncle 15–20 mm (0.59–0.79 in) long. Flowering occurs from early autumn to spring and the fruit is a brownish-yellow berry 10–15 mm (0.39–0.59 in) in diameter.

Solanum quadriloculatum was first formally described in 1861 by Ferdinand von Mueller and the description was published in Fragmenta Phytographiae Australiae. The specific epithet (quadriloculatum) means '4 celled'.

Tomato bush grows along disturbed roadways, clay, loam soils and dry locations that are seasonally flooded in New South Wales, Queensland, South Australia, Western Australia and the Northern Territory.