Background: There is a considerable body of research linking child well-being with future outcomes for children. In recent years monitoring and promoting child well-being has been high on the UK government agenda and has attracted a great deal of theoretical interest. Despite existing research and given the importance of a precise definition, there remains a lack of knowledge about what well-being actually means to children.An independent literature search highlighted that while researchers have made some effort to understand what well-being means to children there are still significant gaps in the literature, including an understanding of how children's views of well-being vary across different age groups.Participants: Nine participants were selected from three different age groups (four, seven and eleven year olds). The sample included a mix of males and females and all participants were reported to have adequate language skills and none were identified as having special educational needs.Method: This is a purely qualitative study utilising an in depth survey research design. Semi-structured interviews were carried out with each child and each participant was asked to take photographs of and describe artifacts which they considered to be important to their well-being.Analysis/ Findings: Data were analysed using thematic analysis. Data analysis was conducted in discrete data sets defined by age group. Then compared across age groups to gain understanding of how children's views of well-being develop with age.Well-being appeared to be conceptualised as an evaluative judgement which was influenced by well-being domains/factors and emotional experience. The complexity of the children's evaluative judgements appeared to become increasingly sophisticated with age. The four year olds were found to understand well-being in egocentric terms whereas the seven and eleven year olds seemed to understand well-being in terms of both their own experiences and the experiences of the perceived other. Two specific developmental considerations were identified which influenced the children's evaluative judgements including individual difference and children's views regarding their ideal life. In addition to this, the component 'self-view' was identified for the eleven year olds. Three domains of well-being were identified which included: 'my relationships', 'my lifestyle and 'myself' and the individual factors relating to these domains appeared to vary and increase in complexity with age. The generalisability of these finding is critically considered within the limitations of the research design.Conclusion/Implications: The findings led to the development of an exploratory developmental model of child well-being. Suggestions are made for future research and potential implications for practice are considered.