In this paper, photoluminescence studies of CuGaSe2 thin films grown by metalorganic chemical vapor deposition on ZnO/glass substrates are presented. Generally, the emission is constituted by a large peak for which the intensity is higher for stoichiometric samples than for Cu-rich and Ga-rich thin films. The peak shifts towards higher energies upon increasing the Ga content. From the dependence on excitation intensity and temperature, the emission is identified as a donor-acceptor pair (DAP) transition.