The gravitational field of a photon on an infinite straight path is a single sheet of plane-fronted gravitational wave accompanying the photon and perpendicular to its track. This field cannot arise from a retarded potential generated by the photon, and I suggest that it arises in the process of emission. The near-field depends on the energy of the photon, but the far-field does not. The field of a steady beam of photons is compared with that of a static material rod, and the differences discussed.