It has smooth, greyish bark, glossy green, linear to narrow oblong adult leaves, flower buds in clusters of up to fifty that are fused at their bases, greenish flowers and fruit in spherical masses.Eucalyptus mcquoidii is a single-stemmed, shrub-like marlock or stunted mallee that typically grows to a height of 0.5–3 m (1 ft 8 in – 9 ft 10 in) or a tree to 10 m (33 ft), but does not form a lignotuber.

[4][5] The specific epithet (mcquoidii) honours Nathan McQuoid, former Fitzgerald River National Park head ranger, for his assistance to the authors.

The subsection Hadrotes contains ten species of which eight do not have oil glands in the branchlet pith.

Together these eight species form series Lehmannianae, a group that has fruit with exserted valves that have fused tips even after the seeds are lost, a feature also shared with the distantly related Eucalyptus cornuta.

[2] This eucalypt is classified as "Priority Two" by the Western Australian Government Department of Parks and Wildlife[3] meaning that it is poorly known and from only one or a few locations.