We conduct two studies to test three hypotheses: (1) Competition increases a firm's customer satisfaction; (2) Rivals' customer satisfaction increases a firm's customer satisfaction; (3) Rivals' customer satisfaction reduces a firm's sales. First, we use store-level customer satisfaction data from a supermarket chain. Next, we consider a range of industries, using brand-level customer satisfaction ratings from the American Customer Satisfaction Index. Results from both studies provide support for the latter two hypotheses, while we only find support for the first hypothesis in the second study.