The 2014 Special Educational Needs Code of Practice embraces the principles of person-centred (PC) planning as a means of developing education, health and care plans. However there is evidence to suggest that person-centred working with pupils in schools is not well embedded. Additionally, an educational psychologistâs (EPâs) role is co-constructed between the EP, the educational psychology service (EPS), and the commissioner of EP services, across each of which PC working may be embedded to varying degrees. Action research (AR) has been identified as an effective approach to both organisational change and professional development (PD). Furthermore, it is argued that changing systemic dynamics supports sustainable PD. A systematic literature review was undertaken to delineate how AR can be used to structure both professional and systemic change for issues relating to social justice. Seven studies met inclusion criteria and found features of AR which facilitate personal PD and systemic change: negotiation, partnership, and participation; reflection; dialogue; and action. Facilitators and barriers of the implementation and use of AR which supports a focus on personal PD and systemic change in relation to issues of social justice in schools were identified as: leadership; a strong, supported facilitator; links to the system; system culture; and time and resources. The AR reported here explored how a group of EPs are developing their own PC practice. The research consisted of a full cycle of appreciative inquiry (AI) with eight members of a local authority EPS. Five inquiry sessions of two hours were completed over a period of seven months to explore EPsâ PC practice. Due to the iterative, cyclic nature of AI, the data generated were analysed session by session in a collaborative thematic analysis, discussion and clarification, and researcher reflections. Reflections were presented to the group at the start of each subsequent session for validation. The research identified a variety of systemic, team, and individual ways that EPs can support and facilitate PC working. An account of the dissemination to professional practice of the research reported in this thesis follows. The paper gives a general overview of evidence-based practice and practice-based research, and of effective dissemination, narrowing to address the implications for EPs and AR specifically. A summary of the implications of the research at different levels is presented, followed by the dissemination and impact strategy which happens in cycles, stages, and at different levels, and is illustrated accordingly.