Introduction: Despite emerging evidence for the effectiveness of school-based suicide prevention programmes worldwide, they have not been rigorously tested in the UK. The Multimodal Approach to Preventing Suicide in Schools (MAPSS) project is one such programme, developed in Melbourne, Australia. MAPSS consists of a psychoeducation session on suicide (universal), screening to identify students at risk (selective), and an online cognitive behavioural therapy intervention for students who disclose suicidal ideation (indicated). Aim: We aimed to conduct a pilot study of MAPSS to determine the feasibility and acceptability of delivery in the UK. Specifically, we aimed to test: 1) psychoeducation, to establish the acceptability and potential benefits of the intervention, and ii) Reframe IT-UK, to establish its suitability and potential benefits for pupils found to be at high risk of suicide. We also tested whether a full trial of MAPSS would be possible, and whether MAPSS could potentially reduce thoughts of suicide in high-risk adolescents and improve mental wellbeing. Methods: 329 Year 10 pupils (aged 14-15) from two secondary schools in Northwest England took part. Quantitative surveys were completed by pupils at three timepoints: baseline, after the workshop, and after Reframe IT-UK. Surveys consisted of a suite of measures including suicide ideation, help-seeking intentions, and knowledge about suicide. Qualitative interviews and focus groups were conducted with pupils (N=13), school staff (N=5), and workshop facilitators (N=4). Quantitative data were analysed using t-tests and qualitative data using thematic analysis. Results: Results indicated that MAPSS was acceptable for use in schools. There were significant decreases from baseline in suicide ideation, depression, and hopelessness scores, as well as increases in suicide literacy, help-seeking intentions, and quality of life. At-risk students presented significant decreases in suicide ideation after Reframe IT-UK. Qualitative data also suggested MAPSS was considered acceptable, but there were some barriers noted. Conclusion: MAPSS was shown to be feasible and acceptable for use in the UK, with the potential to promote suicide literacy and help-seeking and reduce suicide ideation for young people. However, there were some barriers that need to be addressed before a larger trial could be undertaken.