[2][3][4][5] The dwarf gnat orchid was first formally described in 1933 by William Henry Nicholls and Bede Goadby who gave it the name Acianthus tenuissimus.

The description was published in The Victorian Naturalist from a specimen collected near Bayswater.

[8] The specific epithet (tenuissima) is the superlative form of the Latin word tenuis meaning "thin", hence "thinnest".

[9] The dwarf gnat orchid grows under shrubs and grasstrees around winter-wet areas between Perth and Albany with disjunct populations near Esperance.

[2][4][10] Cyrtostylis tenuissima is listed as "not threatened" by the Western Australian Government Department of Parks and Wildlife.