The aim of the present work is to investigate the change in thermal conductivity and stability of copper oxide (CuO) water-based nanofluids, which are prepared by a two-step process, with different concentrations of anionic (Sodium dodecyl sulfate SDS) and nonionic dispersants (Polyvinyl pyrrolidone PVP). Further, CuO nanofluids and nanoparticles have been characterized by XRD, EDX, FESEM, TEM, DLS, and UV to examine the particle size, elemental composition, morphology, particle size distribution, and band gap. Besides, thermal conductivity and stability of all the fluid samples have been measured with respect to particle volume fraction. The interpretation of particle stability in different weight percent of dispersants in base fluids in the presence of PVP dispersant results in a better stabilizing agent than SDS at higher particle volume fraction. Finally, evaluating the effect of lower dispersant concentration (0.1-0.5wt%) and particle size on the thermal conductivity of CuO water-based nanofluids confirmed that the significant enhancement of thermal conductivity is observed at lower dispersant concentration and decreases with increase in particle size. The enhancement of thermal conductivity was found to be 38% and 34% at 0.4wt% of SDS and PVP dispersants.