Background: Over recent decades there has been increasing interest in the importance of spirituality and its impact on the well-being of mental health service users. Nurses have a professional obligation to care for patients holistically and this includes assessing and caring for spiritual needs. However, there is little research regarding the specific issues faced by many mental health nurses. The aim of this study was to explore mental health nurses’ understanding of the spiritual needs of service users and how they reported responding to these needs. Methods: This qualitative study used semi-structured interviews as the method of data collection. Seventeen participants took part which included ten female and seven male participants across a wide range of working-age brackets. The data were subsequently transcribed and analysed thematically using Template Analysis (King, 2012). Findings: Four key themes were identified from the data in relation to personal and professional influences on understanding spirituality and caring for spiritual need; different approaches to nursing spiritually; and ‘fear and anxiety’ which permeated participants’ talk on the research topic in many ways. The findings presented show the complex influences that affected participants’ reported understandings and subsequent responses. Conclusion and recommendations: Mental health nurses experienced anxieties around misinterpreting spiritual need as mental disorder, particularly in service users who experience psychosis and other complex mental health issues. Strategies for engaging with mental health service users who express spiritual and religious beliefs could therefore be a focus for future research. This thesis adds to the wider body of knowledge and may usefully contribute to the development of future practice and policy guidelines so that mental health nurses are better able to confidently and competently understand and respond to spiritual need in service users.