Résumé: Silicon carbide, SiC, polytypes exhibit properties that can vary and can be influenced by factors such as hexagonality percentage, h. The objective of this work is to determine the impact of hexagonality percentage on several elastic and acoustic properties of SiC polytypes (3C, 10H, 8H, 6H, and 4H-SiC). We have successfully formulated relations linking the elastic moduli to the energy gaps (Eg) of the SiC polytypes after an in-depth study of the elastic moduli (Young's modulus E, bulk modulus B, and shear modulus G) in relation to the energy gap Eg. Then, the influence of hexagonality percentage on the elastic properties of SiC polytypes and their acoustic velocities (longitudinal, transverse, and Rayleigh) as well as their critical angles θL, θT et θR was analyzed and discussed to obtain semi-empirical formulas in the form: F(h) = ±h +  , which implies the existence of a near-linear relation between the elastic and acostic properties of the SiC polytypes with hexagonality percentage h. We have obtained results that theoretically support the development of SiC polytypes.