Nanocrystalline ZnGa₂O₄ spinel powders were prepared through a simple and facile microwave-irradiation assisted solution-based route, using ethylene glycol as the reaction medium and, without using any structure-directing agents. The as-prepared product consists of ZnGa₂O₄ nanoparticles, which are crystalline as revealed by X-ray diffraction studies and TEM analysis. Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) studies also show that, the size of these as-prepared nanoparticles is less than 10 nm. The annealed nanopowders show intense blue luminescence, under UV excitation, which makes these nanopowders important in the field of phosphor applications.