Experiences of trauma in childhood and adulthood are highly prevalent among service users accessing acute, crisis, emergency, and residential mental health services. These settings, and restraint and seclusion practices used, can be extremely traumatic, leading to a growing awareness for the need for trauma informed care (TIC). The aim of TIC is to acknowledge the prevalence and impact of trauma and create a safe environment to prevent re-traumatisation. This scoping review maps the TIC approaches delivered in these settings and reports related service user and staff experiences and attitudes, staff wellbeing, and service use outcomes. We searched seven databases (EMBASE; PsycINFO; MEDLINE; Web of Science; Social Policy and Practice; Maternity and Infant Care Database; Cochrane Library Trials Register) between 24/02/2022-10/03/2022, used backwards and forwards citation tracking, and consulted academic and lived experience experts, identifying 4244 potentially relevant studies. Thirty-one studies were included. Most studies (n = 23) were conducted in the USA and were based in acute mental health services (n = 16). We identified few trials, limiting inferences that can be drawn from the findings. The Six Core Strategies (n = 7) and the Sanctuary Model (n = 6) were the most commonly reported approaches. Rates of restraint and seclusion reportedly decreased. Some service users reported feeling trusted and cared for, while staff reported feeling empathy for service users and having a greater understanding of trauma. Staff reported needing training to deliver TIC effectively. TIC principles should be at the core of all mental health service delivery. Implementing TIC approaches may integrate best practice into mental health care, although significant time and financial resources are required to implement organisational change at scale. Most evidence is preliminary in nature, and confined to acute and residential services, with little evidence on community crisis or emergency services. Clinical and research developments should prioritise lived experience expertise in addressing these gaps.