The optimal distinctiveness perspective argues that firms face competing pressures to be both 'like' and 'different from' their peers. On the one hand, institutional scholars assert that firms need to be similar to peers in order to gain legitimacy. On the other hand, strategy scholars insist that firms need to strive to be different to gain competitive advantage. In order to enrich the optimal distinctiveness perspective, the present study builds a conceptual model that addresses the relationships among organisational regulatory legitimacy, entrepreneurial orientation, and SME innovation under the context of China's transition economy. Our empirical results show that organisational regulatory legitimacy has an inverted-U relationship with SME innovation. Further, entrepreneurial orientation strengthens this inverse-U shaped relationship. That is, entrepreneurial orientation magnifies both the positive and the negative effect of organisational regulatory legitimacy on SME innovation. This study echoes to the call to conduct broader optimal distinctiveness research by integrating institutional theory and strategic management. Furthermore, our findings provide new evidence for the strategic balance perspective of optimal distinctiveness. [ABSTRACT FROM AUTHOR]