Background: The demand for residential aged care is increasing due to the ageing population. Optimising the design or adapting the physical environment of residential aged care facilities has the potential to influence quality of life, mood and function. Objectives: To assess the effects of changes to the physical environment, which include alternative models of residential aged care such as a 'home-like' model of care (where residents live in small living units) on quality of life, behaviour, mood and depression and function in older people living in residential aged care. Search methods: CENTRAL, MEDLINE, Embase, six other databases and two trial registries were searched on 11 February 2021. Reference lists and grey literature sources were also searched. Selection criteria: Non-randomised trials, repeated measures or interrupted time series studies and controlled before-after studies with a comparison group were included. Interventions which had modified the physical design