Presents a synchrotron radiation photoemission study of the upper-valence-band states of four ZrSe₃-structure compounds: ZrS₃, ZrSe₃, ZrTe₃ and HfSe₃. The sulphide and selenide spectra exhibit a characteristic five-peak structure in agreement with the calculated ZrSe₃ density of states by Myron et al. (1981) and by Bullett (1979). The nature of these features is established by an interplay between the rehybridization of paired-anion ligand orbitals and the hybridization of unpaired-anion states with cation states. The spectrum of ZrTe₃ exhibits only three peaks that appear related to three of the sulphide and selenide spectral features. The differences between the sulphide, selenide spectra and the telluride spectra are discussed in terms of the very large distance between paired-anion ligands and neighbour cations in the latter compound