The measured phonon-density of states of bulk GaN by time-of-flight neutron spectroscopy has been recently reported by Nipko et al. [CITE]. The authors have also calculated the true partial and total DOS as well as the phonon dispersion curves along major symmetry directions in the Brillouin zone. However, the group-theoretical phonon assignments have not been provided. Based on calculated symmetry allowed modes spanned by displacement representation and on the derived connectivity relations along the major directions in the Brillouin zone we have assigned Nipko's phonon dispersion curves to irreducible representations (species) of the $C^4_{6v}$ (P63mc) space group of GaN.