In this study, we aim to explore the effect of relationship learning on relationship benefits in the context of co-opetition. Additionally, to fill the gap in the literature in relationship learning, we examine the moderating effect of the dark side of co-opetition on the link between relationship learning and relationship benefits based on the relationship tensions perspective. The subject involves manufacturing firms of Taiwan, and 146 effective responses are collected. The results reveal that relationship learning positively influences relationship benefits in co-opetition with balanced tensions. However, when there are imbalances among the relationship tensions, relationship learning has no impact on relationship benefits. Finally, we discuss the theoretical and practical implications of this study and offer suggestions for future research.