Frontline employee behaviors can elicit gratitude, allowing service providers to reap benefits including positive word of mouth. However, research has begun to suggest some behaviors might instead elicit indebtedness, a different emotion not always associated with positive outcomes. Using a qualitative study, we construct a model grounded in the threat to self-esteem theory that delineates differences in employee behaviors that generate these two emotions and the consequences of their elicitation. The model is empirically tested in two studies. Consistent with the threat to self-esteem theory, the findings indicate that customer gratitude arises in supportive employee-customer encounters and drives positive relational behaviors. Conversely, customer indebtedness occurs in threatening employee-customer encounters and possesses the potential to deter positive relational behaviors. As a result, we encourage scholars to appreciate the differences between these two emotions and managers to promote employee behavior designed to generate gratitude and not indebtedness.