Resonant inelastic light scattering is used as a versatile tool for the investigation of semiconductor surfaces and interfaces. Phonon scattering spectra yield direct information on structure, surface orientation, and composition of semiconductor layers as thin as a few monolayers. 'Forbidden' electric-field induced LO-phonon scattering in polar semiconductors leads to information on surface or interface barrier heights. The formation of semiconductor heterostructures is studied 'in situ' for the GaAs/Ge system. Electronic Raman scattering is used widely to investigate subband energies and carrier concentrations in space charge layers at semiconductor interfaces as well as in superlattices.