Many studies have focused on professional development within schools, while this article focuses on ICT (information and communications technology) professional development across schools. The aim of this article is to explore how the encouragement of communities and networks might contribute to ICT professional development across schools in close physical proximity. The study is based on a two-year action research project and interviews with the participants of a lead teacher community across five schools. Although the lead teachers and school leaders played a central role, ICT professional development was dependent on a complex interplay of different types of communities and networks, both within, across and outside the schools. This study illustrates how ICT professional development occurred in both expected and unexpected ways and emphasises the need for professional development to take account of the complex needs of teachers, rather than being a 'one size fits all'.