The green iguana, also known as the American iguana or the common green iguana, is a large,arboreal , mostly herbivorous species of lizard of the genus Iguana. Usually, this animal is simply called the iguana. The green iguana ranges over a large geographic area; it is native from southern Brazil and Paraguay as far north as Mexico.

A herbivore, it has adapted significantly with regard to locomotion and osmoregulation as a result of its diet. It grows to 1.7 m (5.6 ft) in length from head to tail, although a few specimens have grown more than 2 m (6.6 ft) with bodyweights upward of 20 lb (9.1 kg).