Urbanisation is taking place worldwide and rates of mental illness are rising. There has been increasing interest in ‘nature’ and how it may benefit mental health and well-being.

To understand how the literature defines nature; what the characteristics of the nature intervention are; what mental health and well-being outcomes are being measured; and what the evidence shows, in regard to how nature affects the mental health and well-being of children and adolescents.

A meta-review was conducted, searching three databases for relevant primary and secondary studies, using key search terms including ‘nature’ and ‘mental health’ and ‘mental well-being’. Inclusion criteria included published English-language studies on the child and adolescent population. Authors identified the highest quality evidence from studies meeting the inclusion criteria. Data were extracted and analysed using descriptive content analysis.

Sixteen systematic reviews, two scoping reviews and five good quality cohort studies were included. ‘Nature’ was conceptualised along a continuum (the ‘nature research framework’) into three categories: a human-designed environment with natural elements; a human-designed natural environment; and a natural environment. The nature ‘intervention’ falls into three areas (the ‘nature intervention framework’): access, exposure and engagement with nature, with quantity and quality of nature relevant to all areas. Mental health and well-being outcomes fit along a continuum, with ‘disorder’ at one end and ‘well-being’ at the other. Nature appears to have a beneficial effect, but we cannot be certain of this.

Nature appears to have a beneficial effect on mental health and well-being of children and adolescents. Evidence is lacking on clinical populations, ethnically diverse populations and populations in low- and middle-income countries. Our results should be interpreted considering the limitations of the included studies and confidence in findings.