Although leader-member exchange (LMX) theory offers a detailed account of leader-follower relationship building, the importance of LMX agreement as a theoretically meaningful relational phenomenon has received less attention. This has, in turn, limited scholarly understanding of its pivotal role in leader-follower relationships. We conducted a meta-analysis to synthesize the substantive implications of LMX agreement for leader-follower relationships and to further understand which factors may influence its variation across samples. Results from the random-effects metaregression analyses provided strong support for the moderating role of LMX agreement at the between-study level. Specifically, with higher levels of sample-level LMX agreement, the relationships between LMX and followers' task performance and organizational citizenship behaviors were stronger. Moreover, different national culture configurations (i.e., horizontal individualism vs. vertical collectivism) and changes in relationship tenure were significantly associated with LMX agreement. We also examined a host of methodological factors, which generally had a very limited impact on the study findings. Overall, these meta-analytic findings suggest LMX agreement should be considered as a key relational contingency in LMX theory, as it can help unlock the full potential of high-quality leader-follower relationships. Moreover, as a substantively meaningful phenomenon, its variation across situations is intricately related to contextual influences. Based on our theoretical integration and empirical synthesis, we discuss the implications for LMX theory and identify important directions for the next stages of LMX research. (PsycInfo Database Record (c) 2023 APA, all rights reserved).