Gymnophthalmus underwoodi, called commonly Underwood's spectacled tegu, is a species of microteiid lizard, which is found in South America and on certain Caribbean islands.

G. underwoodi is named after British herpetologist Garth Leon Underwood.

The geographic distribution of G. underwoodi includes the islands of Guadeloupe, Martinique, Saint Vincent and the Grenadines, Barbados, Antigua, Barbuda, Trinidad, and Tobago in the Lesser Antilles; and Guyana, Suriname, Colombia, and Venezuela in South America.

It is also present on Dominica, which has been confirmed by both Breuil (2002) and Turk et al. (2010).

Recent incursions on Saba and Sint Eustatius have led to a widely occurring non-native populations on both islands.