Galeopsis tetrahit, the common hemp-nettle or brittlestem hempnettle, is a flowering plant in the family Lamiaceae, native to Europe and northwestern Asia.

It is a herbaceous annual plant growing to 1 m tall; it is a pioneer species and thrives on disturbed sites or roadsides.

The flowers are multicoloured, with purple, pink, or white areas;[1] diminutive, bilateral and snapdragon-like, and are mostly visited by bumblebees.

The leaf blades are hairy and are ovate with a long tapered tip and with regular large teeth on the margin.

The inflorescence forms a terminal spike and is composed of whorls of pinkish flowers with dark markings on the lower lip.