Based on the pseudopotential approach, the lattice vibration and polaron properties in InP under pressure up to 8 GPa have been investigated. At zero pressure, our calculated values for all features of interest are in reasonable agreement with data available in literature. Upon compression, the optical phonon modes at Γ point in the Brillouin zone are shifted towards high energies and their frequencies display a blueshift with rising pressure. The splitting of the longitudinal and transverse optical phonons narrows under pressure, indicating thus a decrease of the ionicity of InP crystal with pressure. It is observed that all physical quantities being studied in this contribution behave monotonically upon compression. To the best of the author's knowledge, the pressure dependence of the polaron properties for InP in the present study is reported for the first time.