Abstract The second-order Raman Spectrum of GaAs has been measured at room temperature by using an argon ion laser with Brewster's angle configuration. A number of critical points have been interpreted by considering neutron inelastic scattering work and detailed critical-point analysis in Ge. The Γ 1 component is the strongest in the spectrum where overtone scattering is dominant. Combination scattering has been observed in the energy region between 300 and 350 cm −1for both Γ 1 and Γ 15 components. The second-order Raman spectrum is compared with the two-phonon overtone Raman intensity, calculated from neutron diffraction data. In the low frequency region, the Raman spectrum shows directly the one-phonon density of states of the TA phonon.