The aim of this study was to build an implementation process model for social-emotional interventions. Case studies were conducted at five primary schools in England nominated as "lead practise" by their local authorities. Data collection comprised interviews with school staff, children and parents, observations of intervention sessions and other settings, and document analysis. Data were analysed using qualitative content analysis. In brief, the process model of Social and Emotional Aspects of Learning small group work indicates that successful implementation is dependent upon a range of factors, ranging from the skills and experience of the group facilitator to the availability of an appropriate physical space to conduct the sessions. Key aspects of the delivery of small group interventions included setting achievable targets for children, providing constant reinforcement of desirable behaviour, and providing opportunities for pupils to verbalise their emotional experiences. We discuss the implications of the model and make recommendations for future development in this area. (Contains 2 figures, 2 tables and 2 notes.)