It is an erect, monoecious shrub with oblong to narrowly lance-shaped leaves, and small white flowers with six or nine stamens.

Micrantheum hexandrum is an erect, monoecious, more or less glabrous shrub that typically grows to a height of about 2 m (6 ft 7 in).

Flowering mostly occurs from October to February, and the fruit is an oval to spherical capsule 6–7 mm (0.24–0.28 in) long.

[2][3][4][5] Micrantheum hexandrum was first formally described in 1847 by Joseph Dalton Hooker in the London Journal of Botany from specimens collected near Launceston.

[8] Box micrantheum grows on rocky sites and near watercourses, often at higher altitudes, from south-eastern Queensland, along the coast and tablelands of New South Wales to scattered places in eastern Victoria and to eastern Tasmania.