Sphaerodactylus parvus is a dwarf gecko endemic to the Anguilla Bank in the Lesser Antilles, West Indies. Aspects of S. parvus ecology were studied at six sites on Anguilla. Geckos were encountered most frequently in association with rock spills, and gecko population densities (0-5.2/m2) were correlated positively with rock densities. A disproportionate number of rocks which harbored S. parvus were on complex substrates of smaller rocks, leaf litter, and small sticks. Geckos became active in the late afternoon and early evening (after air temperature dropped below under-rock temperature). Activity peaked between 1900 h and 2100 h, but S. parvus was active in leaf litter until at least shortly past midnight. Potential problems associated with field studies of these diminutive gekkonids are discussed.