By drawing on the tensions-based view to depict the components of the dark side of relationships, this study presents a conceptual model explaining how the dark side of relationships can moderate the positive relationship between relationship quality and relationship function. The authors test the hypotheses via a mail survey involving 136 manufacturing firms. The results support the hypotheses, which posit that relationship quality is positively associated with relationship function. Moreover, the empirical results partially support the argument of the author that the influence of relationship quality on relationship function is strengthened or weakened when three relationship tensions (namely, behavioral, structural, and psychological tension) are balanced or imbalanced. Theoretical and managerial implications are extracted from this study, and potential future research directions.