Given the limited empirical research applying theory-driven evaluation to curriculum reform, this study employed Chen’s change model, incorporating perspectives from implementation science, to evaluate Taiwan’s national curriculum program. The change model was formulated by integrating formal and stakeholder theories. Data from a survey of 624 upper secondary school teachers across regions were analysed using structural equation modelling. Findings indicated that leading curriculum development was the most crucial leadership action for achieving reform objectives at the school level. Teacher collaboration served as a key mediator beyond its direct effects. The results suggest that teachers collaborate and learn more effectively when schools provide substantial professional support and guidance through curriculum leadership. This study contributes to understanding the strategies school leaders can use to support reform implementation. Additionally, it highlights the feasibility and value of theory-driven evaluation in assessing national curriculum reform efforts.
