Anxiety and depression in young people are common and disabling, and the continued uncertainty about the future over the course of the pandemic may further increase the number of cases. Helping young people with mental distress is an urgent UK government priority to improve the health and wellbeing of the nation going forward. However, young people with emotional difficulties can struggle with accessing mental health support. An alternative or additional source of support that young people may be able to draw on can be found in their social networks. Exemplifying this, social prescribing schemes offer a range of programmes through local organisations, where young people can identify activities that suit their needs and preferences, while also having the crucial opportunity to connect with others. Importantly, social prescribing may be a more viable alternative to accessing and engaging with services for young people where help-seeking is complicated by lower mental health literacy and stigma. Despite this potential of social prescribing, there are few frameworks for understanding why these schemes benefit young people and whether their therapeutic benefits lie in shaping social support networks. There is also a paucity of data on their feasibility, acceptability, and potential effectiveness in reducing symptoms in youth with anxiety/depression. We propose to address these important gaps by working with community organisations and families participating in the Multi-Agency Collective (MAC) project, a social prescribing scheme, coordinated by the HeadStart team in the London Borough of Newham. To better understand why social prescribing works and if it works by enhancing social support, we will run a mixture of individual interviews and focus groups with community organisation representatives (“link workers”) who work directly with young people in these programmes. Qualitative analysis will explore commonalities and differences in practice across the different programmes, to identify mechanisms of change. To assess the feasibility and acceptability of social prescribing and their potential in reducing symptoms for young people with anxiety and/or depression, information will be gathered from a consecutive series of 100 young people and their parents/carers enrolled to the MAC. We will record the total numbers eligible, those who participate, and those who complete their placements. To assess acceptability we will ask young people and their parents/carers to complete a questionnaire, focusing on overall helpfulness in managing symptoms, their enjoyment, whether they would recommend it to a friend, and aspects they liked/disliked. To assess potential effectiveness in reducing symptoms, a diverse subset of 20 young people will be surveyed weekly on anxiety/depression symptoms. Analysis and modelling of these data will determine the proportion of young people in our sample whose symptoms improve over the course of the intervention. These data will lay the ground work for future refinement and evaluation of social prescribing efforts for mental distress in young people. Therefore, continuous engagement in dissemination is essential. In addition to 3 planned academic publications, we will produce a non-academic report and infographic describing the findings to partnering stakeholders, London Borough of Newham Directors and Public Health England.