Oxalis triangularis, commonly called false shamrock, is a species of perennial plant in the family Oxalidaceae. It is native to several countries in southern South America. This woodsorrel is typically grown as a houseplant but can be grown outside in USDA climate zones 8a–11, preferably in light shade.

The deep maroon leaves are trifoliate, like species in the clover genus Trifolium which are commonly called shamrock, hence the name "false shamrock". The leaves fold down at night, when disturbed, and when in harsh sunlight. The white or pale pink five-petalled flowers also close at night.