Lepidosperma tetraquetrum is a sedge of the family Cyperaceae that is native to Southwest Australia.

It is a tufted perennial with brownish inflorescence that appears sometime between November and December or January and March.

Lepidosperma tetraquetrum occurs on sands with black peat near permanent water.

The first description was published by Christian Gottfried Daniel Nees von Esenbeck in the 1846 volume of Plantae Preissianae.

[1] The seed of the plant is favoured by red-eared firetails (Stagonopleura oculata), an endemic grass finch.