Background. Supporting pupils' social, emotional, and mental health (SEMH) development is a task that schools are expected to undertake in England, yet many staff members find it challenging due to their belief that they don't possess the necessary skills.Objective. To evaluate a commercially available, training resource, The Wellbeing Toolkit, aimed at raising the skills of adults working with children in the SEMH area.Design. The Toolkit was adapted and used as training material by a professional team comprised of educational psychologists, clinical psychologists, and specialist teachers, for schools within an eastern region in England. A mixed methodology was employed to evaluate the usefulness of the Toolkit as a training resource, as well as its perceived effectiveness in raising the skills of school professionals working within the SEMH area. Qualitative as well as quantitative data was gathered from the two groups participating in training, as school staff delegates, and as facilitators of training delivery. Descriptive statistics and content analysis were used for data analysis.Results. The findings suggest evidence of improved skills and knowledge in the area of SEMH, with some specific impact on delegates' practice. Implications for practice are discussed.