Lygodactylus williamsi, William's electric blue gecko, was first descovered by biologist William in the 1950's.
Males are bright blue with a black throat and visible preanal pores and hemipenile bulges. The females are greenisch with a copperish shade and have almost no black on the throat, just a few stripes on the throat. Females can easily be confused with juvenile males that are also green, sometimes with a blueish cast. The adult snout-vent length is 5 to 8 cm.
This gecko eats small insects and drinks water from leaves. They are also fond of nectar.
This species is diurnal, an unusual behavior for a gecko in nature.