The associated production of a J/#psi# and a photon in photon-hadron collisions is considered, and shown to be a good probe of the presence of colour-octet mediated channels in quarkonia production, as predicted by the factorization approach within NRQCD. Total and differential cross sections for photoproduction at fixed target experiments and at HERA are presented. Associated J/#psi# + #gamma# production at hadron colliders is briefly discussed. (orig.)28 refs.Available from TIB Hannover: RA 2999(96-147) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman