In today turbulent environment controlling the suppliers' risk could have a key role in escalating the firms' performance. The present study extends the supply chain literature by introducing supplier dependence as a moderator of the relationship between relationship quality and supply risk reduction. Also, the supply risk reduction is also introduced as a mediator between the relationship quality and supply chain performance association. Data from a survey of 143 Iranian manufacturing firms are used to test the research hypotheses using structural equation modelling. As a result, trust and commitment as two dimensions of relationship quality are found to have a significant and positive effect on supply risk reduction. Furthermore, supply risk reduction also has a positive impact on supply chain performance. Consequently, the results indicate that while supplier dependence positively moderates the contingent relationship between trust and supply risk reduction, it has no significant impact on the link between commitment and supply risk reduction.