BACKGROUND: Unpaid carers of adult mental health inpatients often lack support for their well-being and feel excluded from decisions about patient care. AIMS: This scoping review aimed to: synthesise the peer-reviewed literature evaluating the outcomes of brief interventions for unpaid carers of adult mental health inpatients, identify transferable lessons for evidenced-informed practice, and establish future research priorities. METHODS: PRISMA scoping review guidelines were followed to search 12 databases using predefined search terms. Two reviewers independently screened papers and applied exclusion/inclusion criteria. Studies were included if they evaluated the impact or outcomes of interventions. Two reviewers extracted data and assessed study quality. Data were synthesised to categorise types of interventions and evidence for their outcomes. RESULTS: 16 papers met the inclusion criteria, and five types of interventions were identified: those that aimed to (1) increase carer involvement in inpatient care; (2) facilitate organisational change to increase carer support and involvement; (3) provide carers with support; (4) deliver psychoeducation and offer support; and (5) reduce carer stress and improve coping skills. CONCLUSIONS: Whilst evidence of intervention effectiveness was promising, the quality of studies was generally weak. More research is needed to develop an evidence-informed approach to supporting carers during inpatient stays.