Over the last two decades there have been significant increases in the integration of Information Communication Technologies (ICT) in New Zealand schools. Investment in infrastructure, equipment and applications has been supported by a corresponding increase in the funding for Professional Development (PD) provision for teachers in ICT. This is based on the assumption that the level of competence and confidence of teachers in ICT directly impacts on the capacity and capability of schools to positively engage their learners in ICT-supported learning environments. Influenced by the school reforms of the late 1980s (Tomorrow’s Schools) a school-administered model of professional development, the ICT PD Cluster Model, was conceived by the New Zealand Ministry of Education in 1996. This model encouraged groups of schools (clusters) to reflect upon the potential impact and influence of ICTs on their learning communities. The outcome of this process, combined with schools’ existing knowledge of their teachers’ capabilities and confidence in ICT, influenced decisions on the focus, design, delivery and assessment of professional development activities. The dual purpose of this paper is to firstly, review the ICT PD cluster model and describe those key features that could be considered ‘best practice’ and secondly, identify those attributes that either enabled or impeded ICT PD Cluster implementations and the critical organisational and operational success factors which should be followed in any future model of ICT PD implementation.