Tiger snakes are a type of venomous snake found in southern regions of Australia, including its coastal islands and Tasmania. These snakes are highly variable in their colour, often banded like those on a tiger, and forms in their regional occurrences. All populations are in the genus Notechis, and their diverse characters have been described in further subdivisions of this group; they are sometimes described as distinct species and/or subspecies.

Tiger snakes are a large group of distinct populations, which may be isolated or overlapping, with extreme variance in size and colour. Individuals also show seasonal variation in colour. The total length can be up to 2.1 metres (7 ft). The patterning is darker bands, strongly contrasting or indistinct, which are pale to very dark in colour. Colouration is composed of olive, yellow, orange-brown, or jet-black, and the underside of the snake is light yellow or orange. The tiger snake uses venom to dispatch its prey, and may bite an aggressor; they are potentially fatal to humans. Tolerant of low temperatures, the snake may be active on warmer nights. When threatened, they will flatten their bodies and raise their heads above the ground in a classic prestrike stance.

Tiger snakes give birth to 12 to 40 live young; an exceptional record was made of 64 from an eastern female.

Tiger snakes are found in coastal environments, wetlands, and creeks where they often form territories. Areas with an abundance of prey can support large populations. The species' distribution extends from the south of Western Australia through to South Australia, Tasmania, up through Victoria, and New South Wales. Its common habitat includes the coastal areas of Australia.

Tiger snake venoms possess potent neurotoxins, coagulants, haemolysins and myotoxins. Symptoms of a bite include localized pain in the foot and neck region, tingling, numbness, and sweating, followed by a fairly rapid onset of breathing difficulties and paralysis. In a study, the untreated mortality rate from its bites is reported to be between 40 and 60%.

Treatment is the same for all Australian venomous snakes. The pressure immobilization method is used to inhibit the flow of venom through the lymphatic system. Broad, thick bandages are applied over the bite, then down and back along the limb to the armpit or groin. The affected limb is then immobilized with a splint. Identification of the venom is possible if traces are left near the wound. Identifying the snake is not necessary if bitten in Tasmania, however, as the same antivenom is used to treat all Tasmanian snakes' bites. The availability of antivenom has greatly reduced the incidence of fatal tiger snake bites. The number of deaths is now exceeded by the brown snake.