The aim of this investigation is to determine the reinforcing effects of alumina nanoparticle in a diglycidyl ether of bisphenol A (DGEBA) type epoxy resin using different approaches based on in situ Fourier transform infrared spectroscopy, differential scanning calorimetry (DSC), dynamic mechanical, mechanical and microstructure measurements. From the kinetic analysis using the Avrami equation, it has been seen that the kinetic parameters are influenced by the presence of nanoparticle and the used curing temperatures. Differential scanning calorimetry was used to probe the changes in reactivity by analyzing the reaction heat and the glass transition temperature values of the cured composites owing to the presence of nanoparticle and due to the diamine hardener. It was also found that a relatively low concentration of Al2O3 nanoparticle led to an impressive improvement of dynamic mechanical, mechanical, and thermal properties. The scanning electron microscopy (SEM) photographs showed that the surface roughness increased with the addition of nanoalumina.