We report measurements of the polarization and time‐averaged intensity of four‐wave mixing signals from GaAs quantum wells as functions of the pump beam polarizations, laser photon energy, and optical injection density, the latter covering a range of higher levels than has previously been reported. Excitation of heavy‐hole excitons produced a sin2variation of the signal intensity as the pump beam polarizations changed from parallel to perpendicular, while injection of light‐hole excitons led to an approximately cos2dependence. The tuning dependence of the heavy‐hole‐exciton signal revealed a low‐energy signal which is attributed to biexcitons. The dominance of this signal for perpendicular polarization causes the observed sin2variation of the heavy‐hole‐exciton signal. ©1995 American Institute of Physics.