Iguana is a herbivorous genus of lizard native to tropical regions of Mexico, Central America, some Polynesian islands such as Fiji and Tonga, and the Caribbean. The genus was first described in 1768 by Austrian naturalist named Josephus Nicolaus Laurenti in medicum. Iguana consists of two genera, namely gebus green iguana, which is widespread throughout its range and a popular pet, and the Lesser Antillean Iguana, which is endemic to the Lesser Antilles and endangered due to habitat destruction.

The word "iguana" is derived from the Spanish form of the original Taino name for the species, Iwana.

The two species of lizard within the genus Iguana has a dewlap, which is a row of spines running down their back to their tail, and the "eye" of the third on their heads. This eye is known as the parietal eye, visible as a pale scale on the top of the head. Behind their neck are small scales which resemble fingers, known as tuberculate scales. These scales may be a variety of colors and are not always visible from close range. They have a large round scale on their cheek known as a shield subtympanic.

Iguanas have excellent vision and can see shapes, shadows, colors and movement at long distances. Iguanas use their eyes to navigate through crowded forests, as well as for food. They use visual signals to communicate with other members of the same species.

The tympanum, eardrum iguana, subtympanic shield located above and behind the eye. Iguanas are often hard to spot, as they tend to blend into their surroundings. Color scale is the way they hide from larger predators.

Male iguanas have three hemipenes.