Campanula is one of several genera of platycodoniaceae, commonly known as Campanula. Its bell shaped flower has its common name and scientific name - wind bell means "little bell" in Latin.

The genus consists of more than 500 species and several subspecies, distributed in temperate and subtropical regions of the northern hemisphere, with the highest diversity in the eastern Caucasus Mediterranean region. It also extends to the mountains of tropical Asia and Africa.

The species includes annual, biennial and perennial plants, ranging from dwarf Arctic and alpine species below 5cm high to large temperate grassland and woodland species that grow to 2m (6ft 7in) high.

The leaves of a plant are alternate, and the shape often changes. At the bottom of the stem, there are larger, wider leaves, and at the higher part, there are smaller, narrower leaves. Leaf margins may be intact or serrated (sometimes on the same plant). Many species have white latex in their leaves and stems.

Peanuts in panicles (sometimes solitary), having a five lobed corolla, usually large (2-5 cm or longer), mostly blue to purple, sometimes white or pink. Under corolla, 5 lobed sepals form calyx. Some species have a small leaf like growth between each sepal, called "appendages", and the presence or absence of appendages, relative size and posture are usually used to distinguish closely related species.

Fruit is a capsule containing many small seeds.

Campanula species are used as food plants by the larvae of some Lepidoptera species, including the common Pug (recorded on harebell), the spot moth, the ingrained clay (recorded on harebell), the lime spotted pug and the mouse moth.