The present work is a study of phonons and their dispersion in poly(α-aminoisobutyric acid) (PAIB), which is an example of a poly(amino acid) having a 3 1 0 helical conformation. PAIB has been used as a model to carry out conformational studies on proteins and polypeptides. Dispersion curves show two interesting opposite features: (1) a tendency of some curves to crowd or close in near δ = ψ, which is indicative of coupling between various modes, and (2) a divergence of some dispersion curves belonging to species of the same symmetry. The specific heat is obtained from the dispersion curves via the density of states.