In this article young people’s hyper-masculine performances of gender in a Danish institution for young offenders are analysed. Through the ethnographic method of detailed observations two detailed situations of young people, one male and one female, entering a institution for young offenders it is demonstrated that hyper-masculinity is created as a collective frame of meaning creating both possibilities and restraints in concrete situations. Hyper-masculinity is often discussed in relation to criminality as an intensification of hegemonic understandings of what constitutes a ‘real man’ and thus as part of male offender’s identity formation. In this article the relational analysis show that hyper-masculinity is not alone to be understood as the expression of the individual young person’s performances but rather as the dominating institutional frame guiding all gender performances. The observed hyper-masculine frame comprises notions of a ‘real man’ based on performances of overt sexuality, the willingness to commit violence and the limitation of subversive performances.