Coccinellidae is a family of small, rounded (hemispheric), usually bright colored, short-legged beetles, known variously as ladybugs (North American English), ladybirds (British English, Australian English, South African English), or lady beetles (preferred by some scientists).

Unlike most insects, ladybugs have caught people's imagination and are generally held in high regard. In some cultures, they are considered a sign of good luck, whose killing brings bad luck. Their very name (ladybug or ladybird) is believed to be a dedication to the Virgin Mary, mother of Jesus.

It is believed that coccinellids are often brightly colored to ward away potential predators. This defense works because most predators associate bright colors (especially orange and black or yellow and black) with poison and other unpleasant properties. This phenomenon is called aposematism. In fact, most coccinellids are indeed poisonous to smaller predators, such as lizards and small birds. However, a human would have to eat several hundred coccinellids before feeling any effects. Adult coccinellids are able to reflex-bleed hemolymph from their leg joints, releasing their oily yellow toxin with a strong repellent smell. This becomes quite obvious when one handles a coccinellid roughly.