The transition from primary to secondary school is a critical period for children, which, for most children involves stress and anxiety (Jindal-Snape et al., 2020). If negotiated poorly, this transition can have a significant negative impact on children’s short- and long-term well-being and mental health (White, 2020). Despite this, efforts to improve children’s emotional experiences of primary-secondary school transition are minimal in research and face challenges in practice. Very few interventions focus on supporting children’s emotional well-being and these are limited in number, sustainability, and reach. Talking about School Transition (TaST) is a universal, emotional-centred teacher-led support intervention, which was developed to fill this gap in the literature. The evaluation of TaST consisted of a longitudinal questionnaire-based design investigating the efficacy of TaST in improving 143 Year 6 (aged 10 and 11 year old) children’s coping efficacy and adjustment. It was assessed using the outcome variables: Emotional Symptoms, Peer Problems, Coping Efficacy and Transition Worries, in addition to a qualitative process evaluation. Results suggest that TaST had immediate positive implications for participating children who showed a significantly greater reduction in Transition Worries once at secondary school, compared to control group children. TaST has implications for educational practice and policy in elucidating the importance of supporting children’s emotional well-being over this period and demonstrating the viability and success of implementing emotional-centred support intervention in practice.