A 0.65-eV luminescence peak has been observed in GaAs crystals grown in oxygen. The strength of the peak increases with increasing oxygen pressure during crystal growth. The 0.93-eV peak previously reported from electroluminescence measurements on GaAs diodes is observed in photoluminescence to decrease with increasing oxygen pressure and is absent in samples grown under high oxygen pressure. The 0.65-eV emission is not found in GaAs crystals pulled from AlN crucibles or in crystals grown in quartz without added oxygen. These two luminescence emissions appear to be related to the levels observed in optical absorption and photoconductivity measurements on n-type GaAs. © 1963 The American Institute of Physics.