The polarization of photoluminescence (PL) was investigated on (11¯00) GaN grown by metalorganic vapor phase epitaxy. We found that the PL intensity and wavelength have polarization dependence parallel and perpendicular to thecaxis. We quantitatively analyzed the dependence and found that, since the crystal field of wurtzite GaN along thecaxis is strong enough to fix the|z⟩axis ofpfunctions at thecaxis, the difference in symmetry between three valence bands appears as the polarization anisotropy in radiative emission, even in bulk GaN. ©1997 American Institute of Physics.