Delinquent behaviours during adolescence have increased in rate during the past years with serious repercussions on family and personal levels. The data gathered from the Portuguese law enforcement agencies, reporting to 2009, reveal a rise in 318 occurrences of juvenile delinquency compared to 2008, in a total of 3479 registered occurrences. Starting from this reality, using a probabilistic sample of adolescents from Viseu, between the ages of 12 and 16, this study intends to characterize the prevalence of delinquent behaviours in this specific population and analyse the effect of a set of parental and school variables context in the occurrence of these misconducts. As measuring instruments we will adopt the Family Apgar index, School disruption scale, parenting teens connection form questionnaire and delinquent behaviour scale. This study also aims at gathering contextual information that will allow the defining of a socio-demographic and family profile of these adolescents and parents. The final purpose of this research project is that it should leave an empirical contribution for future strategies aimed at delinquent behaviour prevention in adolescence, supported by the creation of good practice manuals.