The species is native to mainland Southeast Asia northeastern Africa and Indonesia.

G. smithii is one of the biggest geckos, reaching a total length (including tail) of 35 cm (14 in)[citation needed] with a SVL of 19 cm (7.5 in)[2][3] The specific name, smithii, is in honor of Scottish zoologist Andrew Smith (1797–1872), who was the founder of the South African Museum.

[citation needed] G. smithii is found in southern Thailand (Satun, Narathiwatk Pattani), Singapore, western Malaysia (Pulau Pinang, Perak, Pahang, Selangor, Pulau Tioman), Myanmar (Burma), India (Nicobar Islands), and Indonesia (Borneo, Sumatra, Pulau Nias, Java).

[2] The type locality is "Prince of Wales' Island" (= Pulau Pinang, West Malaysia).

[6] The sexually mature female G. smithii lays a clutch of two eggs.