In emerging markets, multinational enterprises use international joint ventures (IJVs) to acquire and integrate partners’ complementary resources and improve their competitive positioning. While resource complementarity facilitates mutual learning and synergy creation, various factors can undermine knowledge-sharing and partner relationships, thereby inhibiting the value-realization potential of complementary resources during the post-partnership-formation stage. Drawing on the relational view, this study investigates how IJV partner differences influence the benefits extracted from resource complementarity. Based on a sample of 200 IJVs in China, we find that cultural distance and control asymmetry between partners negatively moderate the positive impact of resource complementarity on IJV performance. Partner market overlap has an inverted U-shaped moderation effect on the impact of resource complementarity. These results offer novel insights into the contingencies affecting the realization of the value of complementary resources in IJVs.