We studied niche segregation among 3 syntopic lizards, Uta stejnegeri, Uma exsul, and Aspidoscelis marmorata, in the sand dunes of Viesca, Coahuila, Mexico. In 2004, we analyzed both microhabitat and substrate niches during a warm season and a cold season. Niche breadth and overlap were calculated, and a selection index was used. Each lizard species selected microhabitats that focused on a single perennial plant species and a specific range of sand compactness. Uta stejnegeri was highly associated with the perennial Suaeda nigrescens and highly compacted sand. Uma exsul was associated with sites with deep, loosely compacted sand and Larrea tridentata. Aspidoscelis marmorata was associated with the occurrence of Prosopis glandulosa and moderately compacted sand. Associations described here could help to develop a future conservation and management program for these sand dunes, where the endemic U. exsul and other species are protected.