Customers are averse to disappointment that arises when economic outcomes fall short of expectations. In this study, we study a two-period model in which the firm may create rationing in either period. In the anticipation of possible disappointment due to stock-outs, strategic customers decide when to purchase and the firm determines the prices and rationing levels in each period. We explore the impact of disappointment aversion on customers' strategic purchasing behavior and the firm's pricing and rationing decisions. Without disappointment aversion, it is optimal for the firm to adopt a uniform pricing policy without rationing. However, when strategic customers are averse to disappointment, a firm may be able to increase profits with an appropriate level of rationing. We analyze both the mark-up and mark-down policies. We show that, in a mark-down scenario, the firm always benefits from disappointment aversion behavior by using an appropriate level of rationing in a low-price period. However, in a mark-up scenario, whether it is beneficial for the firm to induce disappointment aversion behavior depends on how customers frame payoffs in different periods when forming utilities. Particularly, when customers compartmentalize payoffs in different periods to form utilities, the firm should not induce disappointment aversion behavior.