Interactions in molecular systems have crucial influences on their spectral properties. This article concerns three issues relevant to the polarizabilities and Raman scattering of interacting systems. These include: (i) the influence of intermolecular charge transfer on the Raman scattering spectra of charge transfer complexes, (ii) the charge transfer contribution to the surface-enhanced Raman scattering (SERS) for molecules adsorbed on solid surfaces, and (iii) resonance Raman scattering of molecular aggregates in which the excited state interaction (excitonic coupling) is involved.