While the concept of psychological safety has been gaining momentum, research concerning psychological safety in inpatient mental health wards is lacking. To investigate how psychological safety is conceptualised by healthcare staff in inpatient mental health units, and what barriers and facilitators exist. Reflexive Thematic Analysis was used to analyse 12 interviews. Participants conceptualised psychological safety as feeling safe from physical harm, being able to develop meaningful relationships and feeling valued at work. Participants often did not feel physically safe at work, which led them to feel psychologically unsafe. Barriers to psychological safety were reliance on agency workers, punitive management approaches and the inherent risk in working with mental health inpatients. Facilitators included appropriate staffing ratios and skill mix, being able to form meaningful relationships and having access to support. The emphasis on the physical safety element within psychological safety means that existing definitions of psychological safety require extension for the mental healthcare context. However, large-scale research is needed to further understand experiences of psychological safety in this group. A better understanding of the dimensions of psychological safety in inpatient mental health settings could support the development of tools to investigate psychological safety interventions. Organisations could support psychological safety through regular staff supervision and improved staffing ratios and skill mix.