The need for the selection of diesel fuel alternatives for compression ignition engines arises from the ongoing exploration of more sustainable and environmentally friendly options to traditional diesel fuels. The current work focuses on the selection of an optimum diesel fuel alternative among vegetable oil, biodiesel, hydrotreated vegetable oil, emulsion, and alcohol. The comparison criteria among these alternatives are based on performance (brake specific fuel consumption, and brake thermal efficiency) and emissions (NOx, CO, HC, and smoke). Multi-criteria decision making (MCDM) techniques like AHP, ARAS, TOPSIS, and VIKOR were used for the choice of best optimum fuel alternative among these five alternatives. AHP was applied for the calculation of criteria weights, while ARAS, TOPSIS, and VIKOR were utilized to assess and rank the alternatives. Hydrotreated vegetable oil has better performance and lower emissions in comparison to diesel, and hence was ranked as the best diesel fuel alternative in all the ranking methods. Vegetable oil, on the contrary, leads to a significant drop in efficiency, along with an increase in fuel consumption, and hence ranked last. This evaluation is crucial to identify the most suitable alternative that can offer improved efficiency, lower emissions, and overall better performance in compression ignition engines.