Europium doped Yttrium oxide (Y2O3) nanophosphors with different doping concentrations were synthesized by simple and efficient sol-gel method. The structural, morphological and compositional study was carried out by using XRD, FE-SEM, TEM, EDS, XPS, etc. Results demonstrated that the material is highly crystalline with cubic (body centered) structure and the particles apparently are of spherical shape with particle size around ∼10–20 nm. EDS results show the presence of Eu-impurity evenly distributed. Optimization of luminescence properties of the material by varying the concentration and annealing temperature show maximum thermoluminescence (TL) sensitivity at 1600 °C for 10.0 M% of Eu, however, maximum photoluminescence (PL) intensity was achieved after annealing the nanophosphor at 1200 °C. It exhibits a strong red emission with a sharp peak at 612 nm under excitation with UV and visible light (λex = 260, 393, 466 nm). TL studies showed four peaks at 100, 117, 139, and 301 °C. However, the first peak fades completely in a day (apparently due to low peak temperature) but the other three peaks are quite stable. The TL response was found to be linear from 120 Gy to 1.0 kGy but becomes sub-linear later in the dose range 1.0–100 kGy. Display omitted •Y2O3:Eu3+ nanophosphor was synthesized by simple and efficient sol-gel method.•The chemical compositions and binding energy information study was examined by X-Ray Photoelectron Spectroscopy (XPS) technique.•Thermoluminescence (TL) and Photoluminescence (PL) characteristics have been studied.•Y2O3:Eu3+ nanophosphor was exposed by gamma radiation and its TL response was studied up to 100 kGy dose.•The TL glow curves were deconvoluted by Computerized Glow Curve Deconvolution (CGCD) method.