In this study, we evaluate how individual virtues and inter-organizational management control systems (IOMCS) influence buyer–supplier performance through relationship quality. Results from a sample of 232 firms confirm that virtues and IOMCS relate positively to relationship quality and performance, respectively. However, IOMCS lose their positive influence on relationship quality when considered along with virtues. That is, when both variables enter the regression model simultaneously, virtues win. This interesting finding has particular resonance at a time when research on ethics still needs to reinforce its positive effects on the practice of management.