The mental health of children and young people is a significant concern and recent research points to the key role that schools can play in supporting this area. There is a growing interest in school based mental health interventions and at the time of embarking on this study the Targeted Mental Health in Schools (TaMHS) project was a new three year pilot project which aimed to assist Local Authorities (LAs) to develop their own innovative models of mental health support in schools for pupils at risk of, or experiencing mental health problems. The LA in which the study took place was one of 25 wave one 'pathfinders'. The key aim of the TaMHS project in this LA was to improve emotional well-being in nine project schools. The local model sought to achieve this through building capacity at school level via both the provision of a universal / whole school approach and by incorporating targeted interventions for young people who were at risk of, or experiencing mental health problems.The importance of involving young people in the evaluation of mental health services is an increasingly accepted phenomenon and there are a number of benefits of including children in shaping their own mental health provision. This thesis is an evaluative study of practice in the real world which explores young peoples' perceptions of TaMHS after one year of the project being operational within one LA. The study obtains the views of targeted young people in order to investigate some of the perceived successful and unsuccessful factors associated with the project's implementation and to appraise the initial impact of the project. It also examines targeted young people's perspectives with regard to the future development of the project and reviews the utility of pupil voice in helping to improve school based mental health provision. Qualitative data was obtained from 45 targeted young people who had some involvement with TaMHS using nine focus groups which took place in each project school. Thematic analysis was used to enable the predominant key themes to be reported. The findings serve to highlight that the voice of the child can be used to increase understanding of the initial impact of the TaMHS project in one LA, as well as illustrating positive and negative aspects which in turn can lead to suggestions for improvements to school based mental health provision. Predominant areas that young people felt that the project had impacted on included social skills; interpersonal skills; relationships; behaviour; emotional well-being; and access to activities. Key themes which highlight factors that young people viewed as good about TaMHS incorporated learning; behaviour; interpersonal skills; emotional well-being; enjoyment; and activities. Examples of key themes which reflect how young people felt the project could be improved included environment; extending the project; more of the same; and activities. In light of the findings, recommendations for the development of TaMHS and for school based mental health provision in general are offered.