ABSTRACT In this study, we investigate whether returnee directors (Chinese nationals with foreign experience serving as directors) mitigate opportunistic related party transactions (RPTs), a relatively under‐investigated area of research. Using a large dataset of Chinese listed firms, we find that firms with returnee directors are significantly less likely to engage in RPTs (especially abnormal RPTs); this is because returnee directors' international experience and relative independence enable them to serve as effective monitors. This effect is more pronounced in non‐state‐owned firms and those with weak internal governance. Notably, we find that RPTs in firms with returnee directors are associated with improved firm performance. This suggests that returnee directors, while curbing opportunistic RPTs, may facilitate efficient RPTs that enhance firm value. Furthermore, our analysis reveals that independent returnee directors exert a more significant influence in constraining RPTs compared to executive returnee directors. Our findings remain consistent after a battery of robustness tests.