Lupin, sometimes spelled lupine in the US, is the common name for members of the genus Lupinus in the Fabaceae family of flowering plants.

ITIS recognises over 150 species of lupin, and there are also numerous hybrids and cultivars. Some species, such as the Garden Lupin (Lupinus polyphyllus) and hybrids like the Rainbow Lupin (Lupinus x regalis) are common garden flowers. Others, like the Bush lupin L. arboreus are considered invasive weeds when they appear outside their native range.

Lupin leaves (from the bush lupin)

Lupins have a characteristic and easily recognised leaf shape, with soft green leaves are divided into eight to sixteen small, finger-like leaflets that diverge from a central point. They have a long central tap root.

The Nootka Lupin (Lupinus nootkatensis) is common on the west coast of North America, and is one of the species from which the garden hybrids are derived, being valued in Britain for its tolerance of cool, wet summers.