Prostanthera serpyllifolia, commonly known as small-leaved mintbush, is a small shrub that is native to southern Australia It grows up to 0.5 metres in height and has leaves that are ovate in shape and are 1.5 to 3 mm long and to 0.7 mm to 1.3 mm wide. Flowers occur in spring.The species was formally described in 1810 by botanist Robert Brown, based on plant material collected from the southern Eyre Peninsula in South Australia.