BACKGROUND: Public involvement and engagement (PI&E) is increasingly recognised as an important component of research. It can offer valuable insights from those with experiential knowledge to improve research quality, relevance, and reach. Similarly, schools are ever more common sites for health research and, more recently, PI&E. However, 'gold-standard' practice is yet to be established, and activities/approaches remain underreported. As a result, knowledge can remain localised or lost. Diversity and inclusion also remains a challenge. METHODS: This protocol has been informed by UK national guidance, evidence-based frameworks and available implementation literature. It describes both rationale and approach to conducting PI&E activities within a secondary school context. Activities are designed to be engaging, safe and accessible to young people with diverse experiences, with scope to be iteratively developed in line with public collaborator preference. DISCUSSION: Young people should be architects of their involvement and engagement. Ongoing appraisal and transparency of approaches to PI&E in school settings is crucial. Expected challenges of implementing this protocol include facilitating a safe space for the discussion of sensitive topics, absence and attrition, recruiting students with a diverse range of experiences, and potential knowledge and capacity barriers of both facilitator and contributors. Activities to mitigate these risks are suggested and explored.