Habenaria xanthantha, commonly known as freak rein orchid, is a species of orchid that is endemic to far northern Queensland. It has two or three leaves at its base, and up to twenty small white flowers often lacking the nectary spur present on other species in the genus.
Habenaria xanthantha is a tuberous, perennial herb with two or three upright leaves, long and wide. Between eight and twenty white flowers, long and wide are borne on a flowering stem tall. The dorsal sepal is about long, wide and with the petals, forms a hood over the column. The sepals are long, about wide and spread apart from each other and turn downwards. The petals are similar in size to the lateral sepals. The labellum is long, about wide and sometimes has three lobes. When present, the nectary spur is up to long. Flowering occurs from March to April.
Habenaria xanthantha was first formally described in 1869 by Ferdinand von Mueller and the description was published in Fragmenta Phytographiae Australiae. The specific epithet (xanthantha) is derived from the ancient Greek words () meaning "yellow" and () meaning "flower", although no yellow-flowering forms have been seen in the last fifty years.
Freak rein orchid grows in moist to wet woodland on some Torres Strait Islands and on Cape York Peninsula south to Proserpine.