Resonant Raman scattering measurements in an external electric field have been performed in GaAs/AlxGa1-xAs quantum wells. Changes in both the energy and intensities have been observed as a function of the applied electric field and the width of the wells. The variation of intensities depends significantly on the "allowed" (δn = 0) or "forbidden" (δn≠0) character of the transitions. Photoluminescence excitation spectra are presented for comparison. All the results are explained by a model calculation based on a tight-binding scheme including mixing of valence states. The agreement between theory and experimental results is good for the dependence of the transition energies and probabilities on both the applied field and the well widths. © 1987.