Strain characterization of materials through Raman spectroscopy often requires the optical phonon wave vector to be in directions other than those of the strain-modified phonon eigenvectors. As a result, the observed mode frequencies are mixtures of the strain-modified eigenfrequencies. The selection rules for such generalized scattering configurations are derived here for the strained zincblende-diamond family crystals. The formulation is based on the relative magnitude of the LO-TO and the strain-induced splittings. The results are important for the analysis of strain-modified Raman lineshapes and of “forbidden” lines. Specific examples are worked out in detail for externally stressed bulk crystals (90° scattering geometry), and for [001], [111], and [110] strained heterojunctions (backscattering under oblique incidence and/or detection). ©1997 American Institute of Physics.