Nano additive-based vegetable-oil fluids are playing a vital role in conventional thermal appli-cations due to their contribution to improved thermophysical properties. This work is focused on the synthesis and characterization of a novel ZnO-Ag hybrid nanoparticles-based sun-flower oil for thermal applications. Firstly, the ZnO-Ag hybrid nanoparticles were prepared by a wet chemical approach and characterized using SEM and TEM. The synthesized hybrid nanoparticles were then mixed in the sunflower oil to prepare various nanofluids at different volume concentrations ranging from 0.05 to 0.20%. The stability of the prepared nanofluids was investigated as a function of Zeta potential and visual examination. Further, the thermal conductivity and viscosity of prepared nanofluids were measured by the KD2-pro analyzer and Brookfield viscometer. The result showed that the thermal conductivity of prepared nano-fluids was increased up to 21.01% at 0.20% nanoparticles volume concentration. Finally, an artificial neural network model was developed to accurately predict the thermal conductivity of prepared nanofluids.