Diet of two populations of Sceloporus grammicus was determined from Tilcuautla and La Estanzuela, Hidalgo, Mexico. Diet of S. grammicus is primarily Araneae, Insecta (Coleoptera, Dermaptera, Diptera, Hemiptera, Homoptera, Hymenoptera Lepidoptera, and Orthoptera), Mollusca (gastropods), and Reptilia (Sauria). Hymenoptera and Coleoptera were most frequent in the diet of both populations. These groups were more abundant and more diverse in diet of lizards from Tilcuautla than in those from La Estanzuela. Breadth of diet for males from Tilcuautla was B  =  0.108 and for females was B  =  0.101, and in La Estanzuela was B  =  0.183 and B  =  0.095 for males and females, respectively. Overlap between males and females from Tilcuautla was O_jk  =  1.000, with percentage overlap of 97.0–100%, and for La Estanzuela overlap was O_jk  =  0.938, with percentage overlap of 76.3–100%. Based on the feeding-importance value (ViI), coleopterans and hymenopterans were the most important orders in the diet of S. grammicus for both populations and sexes. Diet of S. grammicus is mainly insectivorous with a tendency to specialization on coleopterans and hymenopterans, but this species could be a generalist at some time during the year as indicated by this study.