In this paper we introduce a novel construct, Leader-Member Exchange (LMX) importance, which we position as a meta-perception indicating whether followers view their LMX relationship as personally important or valuable to them. Based on social exchange theory, we examine the extent to which the obligation followers feel towards their leader depends jointly on the quality and the importance of the LMX relationship. We examine how LMX importance influences the process through which LMX quality affects employees’ level of organizational citizenship behaviour (OCB) by focusing on felt obligation (a measure of followers’ reciprocity obligation in the social exchange process) as a mediating variable. Across two studies, we found that high levels of both LMX quality and LMX importance interacted to engender a greater feeling of obligation in followers to repay the perceived favourable exchanges with their leader. Felt obligation predicted leader-rated OCB, demonstrating support for our hypothesised moderated mediation model. However, psychological empowerment, when included alongside felt obligation (in Study 2) did not mediate the LMX-OCB relationship. Overall, our findings extend the focus of LMX theory beyond the confines of LMX quality to incorporate the importance of the LMX relationship.