Studies of ecomorphology reveal fascinating examples of how natural selection can mold intra- and interspecific variation in morphology–habitat associations. Despite a growing appreciation for the influence of other factors on these associations (e.g., sexual selection), our understanding of the consequences of spatial variation in their expression remains limited. Given the known ties between habitat selection and thermoregulation, one underappreciated outcome of such variation might be concomitant divergence in a species’ thermal ecological traits. We capitalize on morphology, habitat use, and thermal data collected on adult sagebrush lizards (Sceloporus graciosus) from eight populations distributed throughout the species’ geographic range to address this limitation. In terms of their morphology, we detected no overall sexual dimorphism in body size, but there was consistent male-biased dimorphism in limb lengths and head width. Although head width and jaw length variation were unrelated to habitat use, larger lizards and lizards with longer legs exploited more open habitats compared to smaller individuals. These ecomorphological patterns were associated with concomitant variation in thermal traits: specifically, substrate temperatures varied geographically, and jointly these temperatures and habitat configuration predicted parallel variation in lizard body temperature. In general, lizards exploiting warmer perches and more heterogeneous habitats attained higher body temperatures. Overall, these findings provide some evidence that lability in thermal traits might be an underappreciated outcome of geographic variation in ecomorphology, possibly providing an important buffer against variable environmental conditions throughout a species’ range.