This publication provides an overview of the situation of adolescents in the developing world and beyond: who they are, where they live and how their needs are - and are not - being met. The analysis derives from a wealth of data from household surveys, including the UNICEF - supported Multiple Indicator Cluster Surveys (MICS). The report finds that adolescents remain vulnerable in critical areas, despite having benefited earlier in their lives from programmes and policies for younger children. It makes a compelling case for increased efforts in advocacy, programming and policy to realise the rights of adolescents and fulfil the Millennium Development Goals (MDGs). This report is the tenth in a UNICEF series that examines progress towards the MDGs for children.