Pterostylis uliginosa, commonly known as the marsh greenhood, is a species of orchid endemic to south-eastern Australia.

Pterostylis uliginosa is a terrestrial, perennial, deciduous, herb with an underground tuber and when not flowering, a rosette of three to eight egg-shaped to elliptic, dark green leaves that lie flat on the ground.

The lateral sepals are erect and partly close off the front of the flower with thread-like tips about 2 mm (0.08 in) long that do not project above the galea.

[3][4][5] Pterostylis uliginosa was first formally described in 1998 by David Jones and the description was published in Australian Orchid Research.

[1] The specific epithet (uliginosa) is a Latin word meaning "full of moisture", "wet" or "marshy",[6] referring to the habitat preference of this species.