This article presents the perceptions of approximately 300 experienced New Zealand principals who participated in a pilot leadership development initiative funded by the Ministry of Education. The Experienced Principals Development Programme (EPDP) underwent a rigorous evaluation that included formative (mid-point) and summative (end-point) feedback to participants and providers over an 18-month period. As the literature on leadership development indicates, particular issues arise for those who are experienced in their leadership roles and have progressed beyond early career challenges. To sustain and develop experienced principals, leadership development programmes need to be relevant, personalized and unique. The evaluation methodology used in this study employed a mixed methods approach comprising quantitative and qualitative analysis of two major participant surveys and data collected for three case studies via observation of delivery events and focus group interviews with participants. The findings confirm that the programme was highly relevant for the participants because it was responsive to individual needs and learning styles. A highly effective component was the school-based inquiry project which was viewed as a conduit for personal development and school improvement. Overall, the programme provided opportunities for both personal and professional learning. (Contains 1 figure and 3 tables.)