Background: Harm reduction has had positive outcomes for people using sexual health and substance misuse services. Clinical guidance recommends these approaches may be appropriately adopted by mental health practitioners when managing some people who self-harm. There has, however, been very little research in this area. Methods: We explored practitioners' views of harm reduction as a strategy for supporting people who self harm. The Self Harm Antipathy Scale (SHAS) was administered to a random sample of 395 mental health practitioners working on 31 wards in England, semi-structured interviews were then conducted with 18 survey respondents. Results: Practitioners who had implemented the approach reported positive outcomes including a reduction in incidence and severity of self-harm and a perceived increase in empowerment of service users. Practitioners with no experience of using harm reduction were concerned that self-harm would increase in severity, and were unsure how to assess and manage risk in people under a harm reduction care plan. Some fundamentally disagreed with the principle of harm reduction for self-harm because it challenged their core beliefs about the morality of self-harm, or the ethical and potential legal ramifications of allowing individuals to harm themselves. Limitations: This study was conducted solely with practitioners working on inpatient units. The majority of staff interviewed had no experience of harm reduction and so their concerns may not reflect challenges encountered by practitioners in clinical practice. Conclusions: Harm reduction is being used to support people who self-harm within inpatient psychiatry and some practitioners report potential benefits of this approach. However, this raises particularly complex practical, ethical and legal issues and further research is needed to assess the safety, acceptability and efficacy of the approach.