This article examines the effectiveness of action research as a continuous professional development (CPD) tool. The aim of the CPD programme was to support 14 community-based Early Childhood Care and Education (ECCE) centres in Ireland to improve quality in their settings through the implementation of the national quality and curriculum frameworks for early childhood education. A community action research approach informed the development of the programme and ensured that plans were implemented. Learning communities, reflective practice and professional dialogue were key elements. Participants found the programme easy to understand and useful to their practice. The combination of purposeful peer interaction and learning through action helped improve the quality of teaching and learning in the settings. Action research supported the implementation of change by helping participants develop the skills needed, both individually and collectively, to deliver outcomes they really cared about. (author abstract)