Gamma radiation effect on the photoluminescence of thin films of conductive polymer MEH-PPV, PbS quantum dots (QDs) and MEH-PPV–PbS (QDs) nanocomposite have been studied. Thin films were obtained by centrifugation. Samples were irradiated with exposure doses (in Gy): 0; 1,84·104; 4,18·104; 6,73·104. Photoluminescence of the polymer MEH-PPV was established to change nonmonotonically with an increase in doses, which might be due to running the oppositely directed, competing processes under the action of gamma quanta, namely destruction and cross-linking of polymer chains. Significant polymer’s restructuring took place under gamma-rays. Photoluminescence intensity of PbS QDs fell approximately twofold after irradiation with doses mentioned above, the intensity maximum shifting to the short-wavelength region. This behavior was due to a change in the energy structure of the QDs. The effect of gamma quanta on the QDs photoluminescence was analyzed.