This document presents a methodology for supplier selection using the Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) method combined with entropy weight. It involves using a decision matrix to evaluate suppliers based on multiple quantitative and qualitative criteria. The weights of each criterion are determined using an entropy weight calculation. The TOPSIS method is then applied to rank suppliers based on their distance from the ideal positive and negative solutions. An illustrative example is provided to demonstrate the step-by-step calculations for applying this methodology to a supplier selection problem involving four suppliers and five evaluation criteria.