INTRODUCTION: Nursing staff are frequently exposed to high-risk patient behaviours within inpatient health services, yet staff commonly report a lack of training and support in managing these behaviours. AIM: The aim of the study was to examine nursing staff experiences of high-risk behaviours in inpatient mental health settings. METHODS: Four electronic databases (CINAHL, Medline, PsycINFO, EMBASE) were searched. The protocol for this review was prospectively registered in PROSPERO (Ref: CRD42022334739). A meta-synthesis of nursing staff's experiences of high-risk behaviours in inpatient mental health settings was conducted. RESULTS: We identified 30 eligible studies. Six themes were constructed from the meta-synthesis: the social contract of care; the function of risk behaviours; the expectation of risk; risk as a relational concept; navigating contradictions in care; the aftermath. DISCUSSION: Nursing staff conceptualize risk as a meaningful behaviour shaped by patient, staff and environmental factors. Managing risk is an ethical dilemma for nursing staff and they require more training and support in ethical risk decision-making. IMPLICATIONS FOR PRACTICE: Inpatient mental healthcare services should formulate and manage risk as a relational concept comprising staff, patient and environmental factors. Future research and clinical practice should place further consideration on the varied experiences of different types of risk behaviours. RELEVANCE STATEMENT: Nursing staff are frequently exposed to high-risk patient behaviours within inpatient health services, yet staff commonly report a lack of training and support in managing these behaviours. This systematic review offers insights into how high-risk behaviours are experienced by nursing staff and makes recommendations about how to improve the understanding and management of them. Inpatient mental healthcare services should formulate and manage risk as a relational concept comprising staff, patient and environmental factors. Future research and clinical practice should place further consideration on the varied experiences of different types of risk behaviours.