Rationale: With knowledge of Special Educational Needs and Disability and systemic practice, Educational Psychologists (EPs) have a distinct role working in Youth Justice Services (YJS). The Taylor Review (2016) identified the need for a multi-agency approach, training and understanding of Speech, Language and Communication Needs (SLCN) in YJS. Aims: This practitioner research aims to increase staff confidence, knowledge and understanding of SLCN and develop a multi-disciplinary SLCN pathway to support assessment and intervention. Method: A four-phase collaborative action research design based on the RADIO framework used mixed methods, including SEND data analysis, informal interviews, pre- and post-questionnaires, observations, and a review of resources. Quantitative data from pre- and post-training measures and a six-month follow-up were compared. Informed by grounded theory (Strauss & Corbin, 1998), themes emerged from the qualitative data. Findings: Following training, staff reported changes in practice; 83 per cent of staff reported using the SLCN pathway to support casework and referrals. Five areas for development emerged: Staff roles and experience, knowledge of SLCN, specialist roles and responsibilities, understanding good SLCN practice and resources. Limitations: Findings reflect SLCN in this local context. The mixed methods approach compromised the reliability and validity of findings. The role and bias of the practitioner-researcher is noted. Future research should include children's views. Conclusion: Working in multi-disciplinary YJS teams, EPs can support organizational change by developing staff knowledge, confidence and understanding of SLCN through training, consultation surgeries and the development of a SLCN pathway. A unique contribution of the project was the implementation of a Quality First Communication approach (QFC).