Abstract Single-crystalline β Ga 2O 3 was studied by Raman spectroscopy between 10 and 1000K. A complete valence force field was obtained. The agreement between observed and calculated Raman active frequencies is 0.8% for the whole spectrum. The potential energy distribution shows that stretching and bending modes are not independent. A complete description of the modes is given in terms of cartesian displacements. The temperature dependence of the Raman band half-widths was studied and is discussed in terms of anharmonicity at high temperature; the broadening which appears above 100K seems to be related to the appearance of defects. Our spectra are better understood in terms of the C2 m space group proposed by Geller rather than P1 as recently proposed by G. M. Wolten and A. B. Chase ( J. Solid State Chem. 16, 377, 1976).