Juvenile delinquents, meaning offenders who are younger than 18 years old, in Switzerland have been and still are a socially and politically controversial topic. After several years of decreasing, the statistical numbers showed for the past five years a slight but constant increase in juvenile delinquency. In this review article the authors describe the progression and development of juvenile delinquency, introduce the main theories and explanations related to juvenile delinquency from different viewpoints and give an overview over “what works?” concerning young people who exhibit delinquent behavior with special consideration to the Swiss juvenile system. Because juvenile delinquency has multidimensional origins the authors plead that a multidimensional approach is necessary in order to be effective in preventing crime.