Union Island, St. Vincent and the Grenadines (8.4 km²) has an unusually diverse reptilian fauna for such a small area, but lacks native or well-established introduced amphibians. In June 2010, we conducted a rapid assessment of 10 sites (coastal or with some variation of dry forest habitats) chosen on the basis of vegetative complexity, height and extent of canopy, and degree of human disturbance. We encountered 10 of the 15 species recorded from Union, missing only a few secretive litter-dwelling or fossorial forms and a recently introduced species for which the current status is unknown. Shannon-Weiner indices of diversity were negatively correlated with vegetative complexity, but the density of Anolis aeneus, the most frequently encountered species, was positively correlated with complexity. We supplemented the rapid assessment with visual surveys for Corallus grenadensis, an arboreal boid, smaller individuals of which feed largely on anoles. Encounter rates for C. grenadensis were not correlated with anoline densities, which we attribute to the relative paucity of both snakes and their prey on a small, dry island.