 The objective of this study was to determine the accuracy of the orbital index, OI, in estimating sex, ancestry, and age in Brazilian skulls. The results showed that the OI was not accurate for estimating sex, ancestry, and age in this Brazilian sample. The OI was not able to differentiate between male and female skulls, nor could it accurately estimate ancestry or age. Additionally, the OI did not show any significant differences between age, ancestry, and the variables analyzed. Therefore, the OI should be expanded to other populations before it can be used to accurately estimate these parameters. This article was authored by Larissa Chavez Cardoso Fernandez, Patricia Morera-Rebello, Bianca Marquez Santiago, and others.