Peperomia quadratifolia is a species of terrestrial or epiphytic herb in the genus Peperomia that is native to Peru. It grows on wet tropical biomes. Its conservation status is threatened.
The type specimen were collected at Schunke Hacienda, Peru at an altitude of 1400-1700 meters above sea level
Peperomia quadratifolia is a small, creeping, epiphytic herb that is transiently more or less pilose at the nodes, with a filiform, rooting stem. The leaves are in whorls of about 4 at the nodes. They are rhombic-square, bluntly subacuminate, with an acute base, and are 1-nerved, drying to an opaque green. The terminal spikes are filiform, 40 mm long, with a 20 mm peduncle. The rachis is glabrous with somewhat loosely arranged flowers. The berries are ovoid, pointed, and bear a pseudocupula, with an apical stigma.
It was described in 1936 by William Trelease in ', from specimens collected by Ellsworth Paine Killip & Albert Charles Smith.
The epithet combines the Latin quadratus and folia, referring to the distinctive square or rhombic-quadrate shape of the leaves.
It is native to Peru. It grows as a terrestrial or epiphytic herb. It grows on wet tropical biomes.
This species has been assessed as threatened in a preliminary report.