Morphological variations of the orbital aperture measurements act as parameter for sexual and ethnic determination. The aim of this study evaluated the dimensions of the orbital aperture in Brazilian subjects to verify its relationship to gender. The orbital apertures of 97 individuals were examined through Caldwell radiographic technique. The maximum width and height of the orbits were measured. The inter-orbital distance, which is the minimum distance between the medial walls of the orbits, was also measured. Statistical analysis was performed through the Pearson test for correlation between measurements and Student ttest with 5% significance level to verify the relation between the gender. Determination of significance attributed to non-parametric Kruskal–Wallis and Mann–Whitney tests (p < 0.05). The test of intra-class correlation (ICC) showed satisfactory repeatability (ICC = 0.9932, p < 0.0001) between measurements performed, taken at different time periods. The ICC showed satisfactory repeatability (ICC = 0.9932, p < 0.0001) between measurements performed at different periods. In the t test, significant differences between the genders, the width, and area of the orbital aperture were obtained. In conclusion, if the area of orbital aperture is <8.5 cm2, the skull is likely to be a female; if it is >9.0 cm2, it is likely to be a male. If the width of orbital aperture is <3.5 cm the skull is likely to be a female; if it is >3.5 cm, it is likely to be a male. If the inter-orbital distance is <2.4 cm the skull is likely to be a female; if it is >2.5 cm, it is likely to be a male Ver menos