Fuel scarcity and environmental pollution associated with global warming are the major threats encountered by the operation of off-road vehicles, such as agricultural tractors and construction equipment. Biofuels from locally available resources and waste materials can contribute toward handling this ecological issue. In this work, an attempt has been made to study the performance, combustion, and emission characteristics of a Simpson S217, twin-cylinder tractor diesel engine using soapnut oil methyl ester as fuel. Soapnuts were purchased from organic shops, and oil was extracted by the cold-press method from soapnut kernels. The extracted oil was further subjected to the transesterification process with the presence of KOH and methanol to separate glycerin and fatty acids. Various proportions of soapnut oil methyl ester and diesel were blended on a volumetric basis. The properties of resulting blends SNB10, SNB20, and SNB30 satisfied ASTM biodiesel standards. Experimental investigations were carried out to study the effect of these blends on fuel consumption, thermal efficiency, cylinder pressure, exhaust gas temperature, and tail pipe emissions. The results revealed that the use of biodiesel blends reduced carbon monoxide, hydrocarbon, and smoke emissions with a slight increase in the NOx emission compared to diesel.