Anxiety is a common mental health difficulty in adolescence. The use of Cognitive Behavioural Therapy Approaches (CBTA) to treat anxiety has a broad evidence-base. This research aims to explore a new abbreviated CBTA-based group intervention for Key Stage 4 pupils (aged 14-16) that uses an ongoing training and supervision model delivered by Educational Psychologists (EPs) across four schools, which builds the capacity and skills of school staff to manage low-level anxiety in schools. A mixed methods study was employed to assess any changes in pupils’ anxiety symptoms before and after the intervention, and also to understand pupils’ and group facilitators’ experiences of the intervention. The Revised Children’s Anxiety and Depression Scale (RCADS) was used to measure any changes in anxiety symptoms before, immediately after, and two months after the intervention (n=16). Semi-structured interviews were used to understand pupils’ (n=7) and group facilitators’ (n=8) experiences of the intervention, with interview data analysed using thematic analysis. Following the intervention, on average, pupils’ anxiety levels decreased over time. Results varied across the schools, suggesting that findings may not be generalisable across all contexts. Pupils and facilitators mentioned key aspects of the intervention that supported pupils in alleviating anxiety (e.g. opportunities for containment, reframing negative thoughts to being more positive, reflecting on positive factors in their week, normalising anxiety). Pupils and facilitators also made valuable suggestions as to how to improve the intervention (e.g. greater flexibility to enable the intervention to be more person-centred, embedding a more systemic approach that compliments the complexity of different secondary school settings)