In this study, zinc oxide (ZnO) and gallium-doped zinc oxide (GZO)/polystyrene nanocomposite films were successfully prepared. Highly luminescent powders were synthesized by a simple sol–gel method. XRD, EDX, FTIR analysis techniques, and Raman spectroscopy confirmed that ZnO and GZO nanopowders were successfully prepared. Photoluminescence and ionoluminescence studies of the synthesized powders showed that they have a brilliant blue emission at room temperature. Incorporation of GZO nanoparticles in a polystyrene (PS) matrix resulted in the formation of nanocomposite with stable and strong blue emission. According to the TEM images, the mean size of particles was estimated about 35 and 42 nm for ZnO and GZO nanopowders, respectively. The radiation response of samples was measured using 241Am alpha source. The counting rate in doped sample was improved significantly compared with ZnO composite. GZO composite showed acceptable counting efficiency which is comparable with the other expensive alpha counters. Investigations revealed that GZO/polystyrene nanocomposite can be a valuable scintillation material for the radiation detection applications.