Hypocalymma gardneri is a species of flowering plant in the myrtle family Myrtaceae, and is endemic to the south west of Western Australia.

It is a widely spreading subshrub, with linear leaves and yellow flowers arranged in pairs in leaf axils, with 80 to 105 stamens in several rows.

Both sides of the leaves are same shade of green and there are many tiny oil glands on the lower surface.

The flowers are sessile and usually arranged in pairs in leaf axils with bracteoles 1.5–2.5 mm (0.059–0.098 in) long.

[2][3][4] Hypocalymma gardneri was first formally described in 2003 by Arne Strid and Gregory John Keighery in the Nordic Journal of Botany from specimens collected near Mount Peron by Charles Gardner in the Lesueur National Park in 1948.