Trainers and developers of school leaders across the globe are currently searching for models of best practice leadership development programmes. Are there generic features and principles of design underpinning such programmes? This article argues that corroborative evidence of what works in leadership training and development - to influence principals' knowledge, skills, values and behaviours - is now emerging. It describes a model of best practice in Hong Kong called Blue Skies, founded on and derived from a body of international research-based evidence from successful principal leadership programmes, together with evaluation evidence from another recent Hong Kong leadership programme. First, however, the policy background to leadership preparation in Hong Kong since 1990 is outlined. This is followed by an explanation of the structure for school leader training and development established by the Hong Kong Government since 2000. It is argued that with the structure in place, attention has been able to shift to the design principles of effective leadership programmes that maximize leader learning. Designs based on research evidence of what works emphasize, inter alia, learning linked to real school contexts, substantial involvement of trained and experienced principals as mentors, flexibility to meet diverse needs, multiple opportunities for reflection, and cohort bonding and networking - all of which form the platform for Blue Skies. Copyright © 2006 Taylor & Francis.