The Madagascar Giant Day Gecko, as its name indicates, is endemic to Madagascar, but only to the far northern part. Large for a gecko, it can grow to a foot (30 cm) in length (but more usually to 25cm) and is active during the day. Previously considered a subspecies of the related Madagascar Common Day Gecko (see below), it was split out to its own species on DNA evidence.

The beaded scales are bright green on the topside and offwhite on the underside, both never with a bluish hue, and there are variable red spots and markings on head and body. The lateral red stripe on the head never goes beyond the eye, unlike that of the related Madagascar Common Day Gecko. The female sometimes has throat pouches storing calcium for her egg shells. An arboreal species, like most geckos they also like walls and inside houses where they can find insects. They can walk across glass and ceilings with ease.

The Madagascar Common Day Gecko is endemic to the eastern side of Madagascar. A large gecko, although usually smaller than the related Giant Day Gecko above, it can grow to some 22cm long and is also active during the day.

It is visually similar to its giant relative and has similar arboreal habits in its different geographical region. In addition to usually being somewhat smaller, there are a few other visual differences, the key two being: the red lateral line on the face can be elongated beyond the eye and the bright green topside and light underside can sometimes have a bluish tinge.