Policymakers and practitioners are seeking answers to the youth employment challenge; looking for ideas and evidence on what works and why, in order to improve the labour market conditions of young people. Youth employment interventions, such as entrepreneurship promotion, training and skills development, employment services, mentoring and subsidized employment are considered common measures to improve youth labour market outcomes. Yet few overview and cross-country studies have reviewed and analysed their impact on such outcomes and what determines success among youth. Labour market interventions to be examined by this systematic review fall into the category of Active Labour Market Programmes (ALMP). ALMPs require active participation in programmes that enhance labour market integration, a requirement which differentiates them from other labour market -- and social protection -- policies, such as unemployment insurance schemes and non-conditional transfers. In the case of ALMPs, the economic rationale relies on market clearing, i.e. labour demand and supply matching and market efficiency through, for instance, job-search assistance, labour market information, and pre-screening of programme applicants. ALMPs can also enhance labour supply through training, foster labour demand through labour-intensive public employment programmes, entrepreneurship, and self-employment measures, or alter the structure of demand by offering employment subsidies. Even though the number of studies contributing to rigorous evidence on the effectiveness of ALMPs has increased over the past decade, many fundamental questions remain unanswered, particularly with regard to context, programme type, design features and target groups. With the aim of impacting policymaking and programming with informed recommendations, this systematic review will take stock of the available evidence and examine changes in labour market outcomes prompted by labour market interventions for youth.