INTRODUCTION: In England, increasing numbers of young people seek help from emergency healthcare services, such as ambulances and emergency departments, after they self-harm. One contributing factor is a lack of meaningful and available community-based alternative sources of support for self-harm. It is not clear what helps young people in this context, how or why. This research aims to understand which resources are available in the emergency setting for young people (aged ≤25 years) who self-harm in England, and how and why they produce their intended and unintended effects. METHODS AND ANALYSIS: A realist review is a theory-driven interpretive approach to evidence synthesis. It provides realist logic of inquiry to produce an explanatory analysis of how and why resources work, for whom and in what circumstances. This review has two key components
one will identify the resources available in England for young people who self-harm in the emergency setting, the other will identify initial programme theories from the international literature. The review will closely follow Pawson's five iterative stages: (1) clarifying scope, (2) evidence search, (3) article selection, (4) data extraction and organisation, and (5) evidence synthesis. Published and grey literature will be reviewed and included. Three key stakeholder groups will be involved throughout the review process, namely two patient and public involvement (PPI) groups (one for young people, one for parents and carers) and an interdisciplinary group of healthcare professionals. ETHICS AND DISSEMINATION: Ethical approval is not required for this review. Results will be reported according to Realist And Meta-narrative Evidence Synthesis: Evolving Standards publication and quality standards. Findings will be disseminated via a peer-reviewed publication in a scientific journal, conference presentations, a study website, an animated video shared via social media and other avenues identified by our PPI groups. PROSPERO REGISTRATION NUMBER: CRD42025638539.