Differential association and social learning theory assume delinquent peers to be instigators and reinforcers of delinquent behaviour and norms favourable of delinquency. Control theory, on the other hand, assumes that delinquents will group together with peers that share a common normative and behavioural background. Interactional theory as an integrative paradigm argues that both – influence and selection – processes might be active simultaneously and are embedded in a reciprocal causal relationship. This paper tests the reciprocity between the association with delinquent peer groups, the acceptance of pro-violent norms and violent delinquency during adolescence with data from a German longitudinal panel study in a longitudinal structural equation model. Results indicate that peers, norms and violence are interactionally related and that influence and selection processes are active simultaneously. Moreover, further structural dimensions are able to explain delinquent peer group association, the acceptance of pro-violent norms and violence in early adolescence.