Stock, the common name for a genus of plants. One of the more than 50 species is the common stock, a popular garden and greenhouse plant. Common stock is also called Brompton stock and gillyflower, and there are many different varieties available to the grower. In nature it is a biennial or perennial; in gardening it is generally grown from seed as an annual. Common stock is native to Mediterranean regions.

Common stock is a many-stemmed, bushy plant that grows from one to two feet (30 to 60 cm) high. The oblong leaves are 2 ½ to 4 inches (6 to 10 cm) long. The showy, fragrant flowers are borne in spikes at the ends of the stems and may be in a variety of colors.

Stocks make up the genus Matthiola (or Mathiola) of the mustard family, Cruciferae. Common stock is M. incana.