A local bond-polarization model based on the displacement–displacement Green’s function and the Bornpotential are applied to study the confined optical phonons and Raman scattering of diamond nanowires(DNWs). Also, the electronic band structure of DNWs are investigated by means of a semi-empirical tightbindingapproach and compared with density functional theory within local density approximation. Thesupercell technique is applied to model DNWs along [0 0 1] direction preserving the crystalline diamondatomic structure. The results of both phonons and electrons show a clear quantum confinement signature.Moreover, the highest energy Raman peak shows a shift towards low frequencies respect to the bulkcrystalline diamond, in agreement with experimental data.