There is growing awareness of the benefits of curriculum-based social and emotional learning (SEL) programs in Early Childhood Education and Care settings for children’s social, emotional, and cognitive development. While many SEL programs aim to strengthen teachers’ capacity and capability to foster children’s social and emotional skills, research effort has focused on understanding the impact on child outcomes, with less emphasis on improvement in teaching quality. This systematic literature review examined the effectiveness of universal curriculum-based SEL programs on teacher outcomes. Fifteen studies met inclusion criteria, capturing ten distinct SEL interventions. The findings suggest SEL programs may strengthen teaching quality, particularly the provision of responsive and nurturing teacher-child interactions and effective classroom management. Data were insufficient to ascertain whether participation improved teachers’ knowledge, self-efficacy, or social-emotional wellbeing. The potential pathways between SEL intervention, teaching quality and children’s developmental outcomes are discussed.

High-quality early childhood education and care (ECEC) can strengthen the social and emotional skills that are crucial for children’s ongoing development. With research highlighting an increasing prevalence of emotional and behavioural challenges in young children, there is emphasis on embedding teaching practices and pedagogies to support social and emotional skills within early learning programs. A growing body of research has examined the impact of social and emotional learning programs in ECEC; however, few studies describe the intervention development process, or how educators and other professionals were engaged to increase the relevance and feasibility of the program. The current paper describes the development of the Cheshire Social-Emotional Engagement and Development (SEED) Educational Program, an online learning tool to support early childhood educators to foster children’s positive mental health. Cheshire SEED was designed using five steps of the Intervention Mapping methodology: (i) comprehensive needs assessment to create a logic model of the problem; (ii) creation of program outcomes and change objectives mapped against determinants of educator behaviour; (iii) co-design of theory-based methods and practical strategies; (iv) program development; and (v) adoption and implementation planning. The process and decisions at each step of the IM protocol are presented, and the strengths and limitations of the approach to develop a mental health intervention for ECEC settings are discussed.