Customer-oriented frontline employees are motivated by a strong desire to help customers. While such motivation enhances customer outcomes, it can also encourage frontline employees to engage in customer-directed prosocial behaviors that undermine organizational norms. We consider such a possibility and find that: (1) in their quest to satisfy customers’ needs, customer-oriented employees engage in customer-focused voice and/or pro-customer rule breaking, (2) the extent to which employees perform these behaviors depends on whether they identify with the organization or customers, (3) customer-focused voice enhances while pro-customer rule breaking hinders role performance, (4) the net performance consequences of a customer orientation can be positive or negative, and (5) various contingency factors determine whether rule breaking results in lower performance ratings from supervisors. These findings offer evidence of a customer orientation dark side and, paradoxically, underscore that internally focused marketing efforts are critical for a customer orientation to enhance frontline employee performance.