Purpose: This study explored the relationships between principals' distributed leadership, school organisational culture and the effectiveness of school innovation management. A questionnaire was administered to gather data from public junior high school teachers in Taiwan. Design/methodology/approach: Using the stratified random sampling method, 1,557 questionnaires were sent to 98 schools in Taiwan, and 1,018 valid questionnaires were obtained. All data were analysed using descriptive statistics and structural equation modelling. Findings: School organisational culture significantly mediated the relationship between principals' distributed leadership and the effectiveness of school innovation management. This mediating role was confirmed through multiple mediation analyses, highlighting the essential link between leadership practices and school innovation outcomes. Originality/value: This study provides new insights into how distributed leadership by school principals can enhance the effectiveness of school innovation management by cultivating a solid organisational culture. The results underscore the importance of distributed leadership in fostering an environment conducive to school innovation.