This study demonstrates the application of the TOPSIS technique for dealing with the Multi-Objective Optimization Problem (MOOP) of a two-stage helical gearbox. The goal is to determine the most effective primary design factors that will improve gearbox efficiency and reduce gearbox length using Multi-Criteria Decision Making (MCDM) technique. Three key design parameters were chosen for this study: the gear ratio of the first stage, and the coefficients of wheel face width (CWFW) for both the first and second stages. Moreover, the TOPSIS technique was deliberately chosen as a MCDM method to tackle the issue of multi-objective optimization. In addition, the MEREC method was selected for calculating the weight criterion. The study’s findings enable the identification of the most effective values for three crucial design parameters in the creation of a two-stage helical gearbox.