Within the competitive supplier base environment, firms are more conscious about selecting the right supplier at the right time by considering a wide range of qualitative and quantitative criteria [1].Supplier selection is an essential part of the procurement process and it is common for any industry. In the current situation of the trade, selecting the right supplier is far more than analysing the price lists and how to cope up with dynamic situations like unpredictable market where there are changes in customer demand with the changing taste, consciousness of quality, price and the delivery time [2]. This research work devises a mathematical algorithm for selecting suppliers and develops the decision support model for apparel industry in Sri Lanka with the incorporation of Pareto analysis and Analytic Hierarchy Process (AHP). The main focus of this research is to address the research problem “How to select supplier in a dynamic situation (order changing)” while achieving two research objectives, to identify the prominent criteria for selecting a supplier for apparel industry in Sri Lanka and to model the supplier selection process in a dynamic situation.