The fantastic least gecko, or fantastic sphaero is a species of gecko found in the Caribbean, on the islands of Dominica, Montserrat, and the Guadeloupe archipelago.

Sphaerodactylus is a genus of geckos from the Americas that are distinguished from other Gekkota by their small size, by their round, rather than vertical, eye pupils, and by each digit terminating in a single, round adhesive pad or scale, from which their name is derived. All species in this genus are rather small, but two species, S. ariasae and S. parthenopion, are tiny, and – with a snout-vent length of about 1.6 cm (0.63 in) – the smallest reptiles in the world.