In this paper, luminescence properties of orthovanadates, Y1− x − yGdxVO4:ySm3+ (where x = 0.05–0.50, y = 0.01–0.05), and the energy transfer mechanism from VO4 3− to Sm3+ via Gd3+ ions were investigated in detail. X-ray diffraction (XRD) analysis confirmed the crystalline phase for synthesized nanophosphor in a tetragonal structure with I41/amd space group. The average crystallite size estimated from XRD was ∼28 nm. Field-emission scanning electron microscopy coupled with energy dispersive X-ray analysis revealed oval shaped morphology and composition of the nanophosphor, respectively. From high-resolution transmission electron microscopy observations, the particle sizes were found to be in the range 10–80 nm. The photoluminescence studies of Y0.77Gd0.20VO4:0.03Sm3+ nanophosphor under 311 nm excitation exhibits dominant emission peak at 598 nm corresponding to 4G5/2 → 6H7/2 transition. The energy transfer occurs from VO4 3− to Sm3+ via Gd3+ ions was confirmed by applying Dexter and Reisfeld's theory and Inokuti-Hirayama model. Moreover, the energy transfer efficiencies and probabilities were calculated from the decay curves. Furthermore, Commission Internationale de l'Eclairage (CIE) color coordinate (0.59, 0.37) has been observed to be in the orange-red (598 nm) region for Y0.77Gd0.20VO4:0.03Sm3+ nanophosphor. These results perfectly established the suitability of these nanophosphors in improving the efficiency of silicon solar cells, light emitting diodes, semiconductor photophysics, and nanodevices. © 2017 King Saud University