The king cobra (Ophiophagus hannah) is a venomous snake endemic to Asia. With an average length of 3.18 to 4 m (10.4 to 13.1 ft) and a maximum record of 5.85 m (19.2 ft), it is the world's longest venomous snake. Coloration of this species varies across habitats, from black with white stripes to unbroken brownish grey. The sole member of the genus Ophiophagus, it is not taxonomically a true cobra despite its common name. The king cobra inhabits forests from South to Southeastern Asia where it preys chiefly on other snakes, including those of its kind. A female king cobra builds a nest to hold its eggs which will be protected throughout the incubation period.

Resembling a true cobra, the threat display of this elapid includes spreading its neck-flap, raising its head upright, making eye contact, puffing, hissing and occasionally charging. Despite its fearsome reputation, it avoids confrontation with humans whenever possible. Altercations usually only arise from a cobra inadvertently exposing itself or being chased; if, however, provoked or cornered, it is capable of striking long in range and high in position. Bites from this species could involve a large quantity of medically significant neurotoxic venom which may lead to a rapid fatality unless antivenom is administrated in time.

Threatened by habitat destruction, it has been listed as Vulnerable on the IUCN Red List since 2010. Regarded as the national reptile of India, it has an eminent position in the mythology and folk traditions of India, Bangladesh, Sri Lanka and Myanmar.