The frilled lizard (Chlamydosaurus kingii), also known as the frillneck lizard, frill-necked lizard or frilled dragon, is a species of lizard in the family Agamidae. It is native to northern Australia and southern New Guinea. This species is the only member of the genus Chlamydosaurus. Its common names come from the large frill around its neck, which usually stays folded against the lizard's body. It reaches 90 cm (35 in) from head to tail and can weigh 600 g (1.3 lb). Males are larger and more robust than females. It is generally grey, brown, orangish-brown, or black in colour. The frills have red, orange, yellow or white colours.

The frilled lizard is largely arboreal, spending most of its time in trees. Its diet consists mainly of insects and other invertebrates. It is more active during the wet season, when it spends more time near or on the ground. It is less observed during the dry season, during which it seeks shade in the branches of the upper canopy. It breeds in the late dry season and early wet season. The lizard uses its frill to scare off predators and display to other individuals. The species is considered to be of least concern by the International Union for Conservation of Nature.