High-resolution sulphur K-edge x-ray absorption near-edge structure spectra have been recorded for europium and gadolinium monosulphides. A comparison of the experimental spectra with the element-projected partial density of unoccupied states calculated using a spin-polarized linear muffin-tin orbital method revealed a rather good agreement. Our analysis suggests that there is a strong hybridization of the 4f and 5d orbitals of the rare earths with the p orbitals of the sulphur which also contribute to the conduction band. The strong d-p and f-p interactions result in a large sulphur p-band polarization which has been confirmed experimentally by the detection of a strong x-ray magnetic circular dichroism signal at the S K edge in EuS.