Graphene oxide coated on GaN was simultaneously reduced and doped with nitrogen via excimer laser irradiation. Nitrogen dopant was originated from the GaN during the laser-induced dissociation at high energies. This phenomenon was confirmed by the absence of C–N bond formation in laser irradiated graphene oxide on SiO2. A top-gated field-effect transistor based on laser reduction of graphene oxide channel on GaN showed n-type behavior via the gate voltage modulation. The present findings indicate a paradigm for the formation of graphene-nitride semiconductor interfaces.