Clinicians navigating the legislation when working with young people and their families in the United Kingdom (UK) may need to use several relevant frameworks of legislation at the same time. This may appear complex in practice. Clinicians need to consider how a young person’s development across multiple domains, for example, cognitive, emotional, moral, social and so on, can have an impact upon their decision-making. Clinicians who work with children and young people often also work with parents or their local authority statutory equivalents, as well as other statutory and non-statutory agencies, to help find the best outcomes for children and young people (CYP). This requires good knowledge of legal frameworks, competence in working within complex multi-agency systems and being able to understand and work with different perspectives around an issue.This chapter specifically discusses aspects of the law in relation to children and adolescents (all those under 18 years) including the Human Rights Framework, Mental Capacity Act 2005, Children Act 1989 (amended 2004), Mental Health Act (amended 2007), and Criminal Justice Act (2003) within England and Wales. We have not addressed the differences in legislation in Northern Ireland or Scotland but have commented on distinct issues where relevant.