Prostanthera campbellii is a species of flowering plant in the family Lamiaceae and is endemic to the south-west of Western Australia. It is an erect shrub with linear leaves and white to cream-coloured flowers with purple striations. Description Prostanthera campbellii is an erect shrub that typically grows to a height of . The leaves are linear, yellowish green, long, wide and sessile. The flowers are arranged singly in two to sixteen upper leaf axils, each flower on a pedicel long. The sepals are green and form a tube long with two lobes, the lower lobe long and the upper lobe long. The petals are white to cream-coloured with purple striations near the base of the lobes, long and fused to form a tube long. The lower lip has three lobes, the centre lobe spatula-shaped, long and wide and the side lobes long and wide. The upper lip has two lobes long and wide. Flowering occurs from July to November. Taxonomy Prostanthera campbellii was first formally described in 1882 by Ferdinand von Mueller in the journal Southern Science Record from specimens collected by John Forrest near the Gascoyne River. The specific epithet honours the politician Thomas Cockburn-Campbell. Distribution and habitat This mintbush grows on granite outcrops and rocky places in the South-West and Eremaean botanical regions of Western Australia. Conservation status Prostanthera campbellii is classified as "not threatened" by the Western Australian Government Department of Parks and Wildlife. References campbellii Flora of Western Australia Lamiales of Australia Taxa named by Ferdinand von Mueller Plants described in 1882