This dissertation consists of three essays considering operation-related decision making issues of a firm in a supply chain. The first essay considers sequential capacity allocation of a supplier whose allocation is made in a sequential manner. We consider two alternative capacity allocations, the efficient allocation and the fair allocation to reduce dissatisfaction of the manufacturers, and compare their performance. The second essay investigates impact of supply chain contracts on environmental innovation in a supply chain. We consider three popular supply chain contracts to promote supplier’s environmental innovation and study their impacts on emission reduction and manufacturer’s profit. The last essay examines organizational structure design issue of a multinational firm (MNF) in the presence of gray market. We investigate impacts of under uncertainty in the local market’s potential and difference in the customer’s valuation between the brand product and parallel import on organizational structure choice of a MNF, i.e., centralization or decentralization.