Both environmental factors and social factors affect an animal's choice of microhabitat. We explored the effects of humidity and the presence of conspecifics and predators on microhabitat selection by Brown-Speckled Sphaeros (Sphaerodactylus notatus; Squamata: Sphaerodactylidae). To test the effect of environmental moisture, we provided geckos a choice between shelters of varying humidity and determined that individuals were significantly more likely to choose more humid shelters. In interaction trials between conspecifics of different sizes and sexes and between geckos and predators, we found that lizards were unwilling to share shelters with conspecifics in all situations. We observed aggressive behaviors such as chasing, biting, and head bobbing and noted that subordinate geckos were unwilling to enter a shelter occupied by a dominant individual even in the presence of a predator.