Polarized Raman spectra in ZnGeP2 crystal have been measured. The symmetry of vibrations has been assigned for every mode but one. The angular dispersion of the extraordinary phonon has been measured, and the result is described by the Loudon–Poulet approximation. Hydrostatic pressure dependence of Raman shift has been measured up to 6 GPa using oriented samples. Pressure coefficients of fifteen Raman peaks have been obtained. Based on the high-pressure study, phonon modes in ZnGeP2 have been examined in terms of phonons in the GaP crystal which is the isoclectronic binary analog of ZnGeP2. © 1999 American Institute of Physics.