We investigate the effects of both carrier and phononk‐space anisotropy on the transport in bulk GaAs photoconductors. Our results show that photogeneration by laser pulses polarized perpendicular to the electric field can delay the initial velocity rise. Furthermore, anisotropic phonon amplification can degrade the turn‐off characteristics. Finally, unliken‐doped semiconductors, we find that the steady‐state velocity‐field values in photoconductors are reduced because of the nonequilibrium phonon modes.