This thesis analyzes a supplier``s quantity discount pricing model for products. The model assumes that the supplier deals with multiple customers and that demands from customers occur in discrete time. And the model treats an all-unit discount rule with a single price break point, and offers the same discount rule to all customers but with joint set-up costs imposed on simultaneous demands. An algorithm is derived for the optimal quantity discount pricing schedule with two decision variables, the discount coefficient and the price break point, which maximizes the supplier``s net profit. For the algorithm illustration, numerical examples are provided.