Purpose: Drawing on concepts from workplace diversity and cognitive evaluation theories (CETs), this study seeks to deepen our understanding of the link between transformational leadership and teachers' creative teaching in a more and more diverse campus. Design/methodology/approach: Survey data involving a total of 895 high school teachers across Taiwan were collected using purposive sampling methodology and analysed with SPSS and SmartPLS software. Findings: The results reveal that the positive relationship between the principal's transformational leadership and teachers' creative teaching is partially mediated by teachers' promotion focus and task interdependence which could reduce the defensive silence and reluctant collaboration found in diverse workplaces. Moreover, principals' cross-cultural competence also moderates such relationship, since it helps transformational leader to take adaptive measures to address the challenges associated with managing differences in perspective and ideas within a heterogeneous workforce. Based on these findings, implication for educational leadership is discussed. Originality/value: Studies have affirmed the positive association between transformational leadership and creative teaching. However, the mechanism sustaining this relationship and how this relationship can further be intensified are still unknown, especially in a more and more diverse education context. Our analysis shows that principals' cross-cultural competence, and teachers' task independence and promotion focus are relevant factors school leaders should consider in enhancing the link between their transformational leadership and teachers' creative teaching.