Homoranthus inopinatus is a plant in the myrtle family Myrtaceae and is endemic to a small area in southern Queensland.

It is an upright shrub with linear leaves and with groups of three to six flowers in leaf axils near the end of branchlets.

[3] Homoranthus inopinatus was first formally described in 2011 by Lachlan Copeland, Lyndley Craven and Jeremy Bruhl from a specimen collected on private property near Ballendean by Jenny and Glenn Holmes in 2002 and the description was published in Australian Systematic Botany.

[4] The specific epithet (inopinatus) is a Latin word meaning "unexpected",[5] referring to the discovery of this species in an otherwise botanically well-known district.

[2] Currently known from a single population, H. inopinatus is threatened by inappropriate fire regimes, grazing and physical disturbance by feral pigs and deer.