It is a small shrub with egg-shaped to almost round leaves, and heads of woolly-hairy flowers.

Spyridium thymifolium is a shrub that typically grows to a height of about 50 cm (20 in) and has slender branchlets covered with white or rust-coloured, woolly hairs.

The heads of "flowers" are 4–9 mm (0.16–0.35 in) in diameter and woolly-hairy surrounded by 2 to 3 more or less round, white, velvety floral leaves and with dark brown bracts at the base.

[2] Spyridium thymifolium was first formally described in 1858 by Siegfried Reissek in the journal Linnaea from specimens collected by Ferdinand von Mueller, near Encounter Bay in 1847.

[5] Spyridium thymifolium occurs in the Southern Lofty and Kangaroo Island botanical regions of south-eastern South Australia.