Abstract Some of the characteristic features of the neandertal face can be explained as adaptations to resist stresses generated by high occlusal loads on the anterior teeth combined with long lever arms of external forces. This interpretation agrees with that offered by Yoel Rak ( J. hum. Evol. 15, 151–164, 1986). However, the nature of the stresses and the mechanical adaptations to counter them are estimated differently. The peripheral position of the walls of the maxillary sinuses imparts torsional resistance in all directions to the projecting part of the face. The inflated maxilla and convex midfacial profile reduce bending in the sagittal plane, as does the straight infrazygomatic contour in the frontal plane. The elimination of angles between the infraorbital plate, the maxillary side walls and the zygomatic body reduces local stress concentrations.