Lepidosperma leptostachyum is a species of flowering plant in the sedge family, Cyperaceae, a native of Southwest Australia.

The first description was given in an 1878 monograph by George Bentham, published in the Flora of Australia series.

[3] Lepidosperma leptostachyum is herbaceous or grass-like in form, growing as clumps around 600 millimetres across.

[1] The species is found in the Southwest Australia region, in a variety of soil types.

They occur on slopes, on black and grey sands, lateritic and peaty soils, or clay, and on gravel.