||This dissertation consists of three essays that explore how unethical behavior develops in adolescence. All three essays use a methodology of lab-in-the-field experiment, but each investigates questions related to unethical behavior from a different perspective. The research presented in this thesis focuses on unethical behavior in two populations: the general population of adolescents and juvenile delinquents. Combining findings from the general and problematic population of adolescents helps us to understand what factors contribute to delinquency and more importantly, what factors may attenuate it. In the first essay, we investigate whether adolescents cheat more when making a decision in groups compared to deciding as individuals and whether the process of group formation matters. The results show that, in general, groups cheat more but the results are driven primarily by younger adolescents while there is no difference between individuals and groups among older adolescents. Interestingly, the process how groups are formed does not play a role. This suggests that tendencies to cheat develop still in the adolescence and that the context in which decision is made, is important. The second essay studies how willingness to obey rules differs between juvenile delinquents and adolescents from the general population. We specifically look at whether juvenile delinquents show signs of ingroup favoritism, how they respond to unfair treatment and if they care about their social image. We find substantial similarities between juvenile delinquents and adolescents from the general population. Even though juvenile delinquents violate rules more often, neither group discriminates outgroup members or respond strongly to unfair treatment, and both do care about their social image. Our results demonstrate that juvenile delinquents are not inherently different from general population adolescents in the domain of rule-violating behavior. Moreover, the care for social image seems to be an influential driver of honest behavior which could be leveraged in therapeutic treatments. The third essay studies if adolescents acquire norms and culture of juvenile detention centers during their terms and how it affects their behavior. Using priming techniques, we estimate a causal effect of a shared identity on cooperation, altruism and cheating. We do not find a significant effect of identity on any experimental outcome which suggests that a shared identity in juvenile detention centers does not play an essential role.