We conducted a comparative study of the cephalic scales in xantusiid lizards. We describe the observed scutellation patterns, compare these to patterns observed in other squamates, and present a revised nomenclature for scincomorph cephalic scales that corrects some previous inconsistencies. Based on anatomical details and topographic relations in xantusiids and other scincomorphs, we suggest the following revisions. In xantusiids, we consider the paired scales previously called “frontals” to be “frontoparietals,” the single scale previously called the “median” to be the frontal, the paired scales previously called “nasals” to be “supranasals,” the paired scales previously called “postparietals” to be “occipitals,” and the single scale previously called the “occipital” to be the “interoccipital.” The paired scales previously called “pretemporals” in Cricosaura typica are considered “parietals,” whereas the pretemporals in Lepidophyma and most Xantusia are considered “supraoculars.” Based on these and other revisions, we propose primary homologies among scincomorph cephalic scales as a framework for future phylogenetic analyses, identify diagnostic characters for Xantusiidae and some of its subclades, and consider some costs of mistaken primary homology estimates to phylogenetic inference.