Gekkonid lizards are shown to have well-developed nasal chemical senses. It is argued that they are unique among squamates so far studied in the degree of their olfactory (as opposed to vomeronasal) development. This contention is supported by evidence from the brain, nasal capsule, tongue, and experimental studies of behaviour. Limited evidence suggests that olfaction functions in food-finding and predator detection; vomerolfaction during investigation of novel stimuli and in reproduction. The conception of gekkonids as members of a ‘visual Ascalabota’ is not supported by these findings. Olfactory specialization makes geckos ideal subjects for tests of the Cowles and Phelan hypothesis of olfactory function and suggests that they might be better subjects than snakes for future studies of dual olfactory form, function and evolution in a nonmammalian lineage.