<p>Thermal energy storage systems are important in solar thermal systems, photovoltaic cooling systems, and energy-efficient buildings, yet they are constrained by the low thermal conductivity of conventional PCMs. To overcome this drawback, nanoparticles and hybrid nanoparticles have been widely used to enhance thermal conductivity. The paraffin wax, in the present case, was functionalized with hybrid nano-alumina (Al₂O₃) and nano-boron nitride (BN) to improve thermo-physical properties. Hybrid nano-dispersed PCMs were prepared with nanoparticle loadings of 0.5%, 0.7%, and 0.9% by weight. Structural and morphological properties were analysed using X-ray diffraction (XRD) and field-emission scanning electron microscopy (FESEM), and thermal behaviour was evaluated using thermogravimetric analysis (TGA), thermal conductivity, and differential scanning calorimetry (DSC). The results show that the percentage weight of hybrid nanoparticles significantly affects the thermo-physical properties of paraffin wax. The nanoparticles were uniformly dispersed, resulting in a maximum increase in thermal conductivity of about 58% compared to pure paraffin wax. This addition of nanoparticles led to a small decrease in the melting peak temperature and a small decrease (6%) in the storage capacity of the latent heat. Overall, the results substantiate the fact that hybrid Al₂O₃ -BN nanoparticles can significantly improve the thermal conductivity of paraffin wax, which proves their possibility to be put into practice in the context of more sophisticated thermal energy storage.</p>