This review summarises the research literature on children's and parents' involvement in social work decision making, which is regarded, in policy terms, as increasingly important. In practice, however, it tends to be messy, difficult and compromised. Different individuals or groups may have different understandings of participation and related concepts, while differences of age and disability also mediate effective user engagement. The literature highlights common themes in effective participatory practice with both children and their parents. Central to this are the establishment of relationships of trust and respect, clear communication and information and appropriate support to participate.