Taraxacum officinale, the dandelion or common dandelion, is a herbaceous perennial flowering plant in the daisy family, Asteraceae. The common dandelion is well-known for its yellow flower heads that turn into round balls of many silver-tufted fruit, which disperse in the wind. These balls are sometimes called "clocks" or "blowballs".

Originally native to Eurasia, as a result of its hardiness and easy propagation, the dandelion has become widely established across several continents. It has been introduced to southern Africa, the Americas, Australia, and New Zealand. It grows in temperate regions of the world in areas with moist soils. They are able to grow in a variety of environments and are tolerant of crowding, extreme temperatures, and low moisture.

The dandelion is often considered a weed, especially in lawns, but it is increasingly being recognised in its native regions as useful for attracting birds and pollinating insects. In one study, it ranked as the fourth most important source of pollen. Although dandelion pollen is considered to be an early food resource for some emerging pollinators in spring, it has also been found to lack certain essential nutrients and can lead to declining brood health for bees.

The leaves, flowers, and roots are sometimes used as food and in herbal medicine.