Humulus lupulus (common hop or hop) is a species of flowering plant in the Cannabaceae family, native to Europe, western Asia and North America. It is a dioecious, perennial, herbaceous climbing plant which sends up new shoots in early spring and dies back to a cold-hardy rhizome in autumn.

Hops are described as bine plants rather than vine because, unlike vines, they have stiff downward facing hairs that provide stability and allow them to climb. These shoots allow H. lupulus to grow anywhere from 4.6 to 6.1 metres (15 to 20 ft). Hops have fragrant, wind-pollinated flowers that attract butterflies.

The female cone shaped fruits from H. lupulus are used by breweries to preserve and flavor beer, and so H. lupulus is widely cultivated for use by the brewing industry. The fragrant flower cones, known as hops, impart a bitter flavor, and also have aromatic and preservative qualities. H. lupulus contains myrcene, humulene, xanthohumol, myrcenol, linalool, tannins, and resin.