Mineral oil is the most frequent insulating liquid used in oil‐immersed transformers for electrical insulation and heat dissipation. However, oil‐based nanofluids are becoming more popular in scientific research as they have proved to have better dielectric and thermal characteristics. When applying these nanofluids into actual transformers, they would be exposed to thermal and electrical stresses. Thus, The aim of the authors is to investigate the generation pattern of dissolved gases in nanofluids under thermal and electrical faults and to assess the applicability of traditional Dissolved Gas Analysis (DGA) techniques if oil‐based nanofluids are used in transformers. Oil‐based nanofluid samples were prepared using a magnetic stirrer and an ultrasonic homogeniser and then subjected to simulated thermal and electrical faults in the laboratory using properly sealed test cells. Three types of metal oxides, Silicon dioxide, Titanium dioxide, and Aluminium oxide nanoparticles, have been used to prepare nanofluids with 0.02 g/L and 0.04 g/L concentrations. The gases released and dissolved into oil due to the simulated faults were analysed and compared to traditional mineral oil as a benchmark. The dielectric dissipation factor was obtained and analysed for all samples. According to the findings, the presence and concentration of nanoparticles were shown to influence the amount of gases produced. As a result, this research is crucial in guaranteeing that traditional DGA techniques can be employed in transformers that use oil‐based nanofluids.