Eucalyptus spathulata, commonly known as swamp mallet, narrow leaved gimlet or swamp gimlet, is a species of mallet that is endemic to Western Australia. It has a dense crown, smooth, satin-like bark, glossy green, linear leaves, flower buds in groups of three or seven, white flowers and cup-shaped to conical fruit.

Eucalyptus spathulata is a low-branching mallet with a dense crown that typically grows to a height of 8–12 m but does not form a lignotuber.

The bark is smooth, satin-like, greyish brown or reddish brown on the trunk and branches.
Swamp mallet is found on flats, broad valley floors, on rises, in and around saline depressions and along the edges of salt lakes in the southern Wheatbelt and inland Great Southern regions of Western Australia where it grows in sandy or sandy-clay soils over granite.

Eucalyptus spathulata has a high to moderate growth rate and can live to over 15 years. It can be grown in saline and poorly drained situations.

It is planted in gardens as an ornamental and as a windbreak. The bark is rich in tannin and the leaves contain cineole.

The tree is both drought and frost tolerant and can withstand salt laden winds.