It is a shrub with thin, cylindrical leaves and white flowers with a pink central stripe, usually arranged singly in leaf axils.

Philotheca wonganensis is a shrub that typically grows to a height of 1 m (3 ft 3 in) with corky branchlets.

The leaves are thin, scattered, needle-shaped, 5–10 mm (0.20–0.39 in), sometimes glandular-warty, and channelled on the upper surface.

The flowers are arranged singly in leaf axils on a thin, club-shaped pedicel about 5 mm (0.20 in) long.

[3][4][5] This philotheca was first formally described in 1982 by Paul Wilson who gave it the name Eriostemon wonganensis and published the description in the journal Nuytsia from specimens collected by Kevin Kenneally near Wongan Hills township in 1980.