This thesis, Gender and girls in deprivation of liberty: a study of the socio-educational care policy in the state of Rio de Janeiro, analyses the organization of this policy following the approval of Resolution 119 of 11 December 2006 by the National Council for the Rights of Children and Adolescents (Conanda), which establishes the basic guidelines for the organization and operation of the National Socio-Educational Care System (Sinase) for adolescents who are accused of committing an offence. This is a qualitative study, which uses the content analysis method to examine normative documents and the content of interviews with operators of the Rights Guarantee System (SGD), with the girls and their families on the subject and whose theoretical framework focuses on gender approaches and the ways in which gender oppression is expressed in the practice of care, as well as its effects. The author analyzes how female adolescents between the ages of 12 and 18, who are serving a detention order, are perceived and attended to in terms of their rights and demands, highlighting physical and mental health issues, sexual and reproductive rights, motherhood and family relations, due to their gender identity or expression. She concludes that care today still follows a masculine logic, which from the formulation of socio-educational policy to the execution of the measure makes girls invisible and secondary, denies their rights, aggravates their precarious living conditions and strengthens existing systems of oppression. Until the 2000s, studies on socio-educational care were centered on male adolescents, since they have historically been the majority of those serving both open and custodial sentences. However, with the approval of this Resolution, the theme of ethnic-racial diversity, gender and sexual orientation was defined as the guiding principle of pedagogical practice and transversal to the entire system. In the following years, the debate advanced in relation to meeting the specific needs of girls, revealing a scenario of inequalities, discrimination and punishments based on gender, skin color and social class. The author therefore defines three points for understanding the policy in question: the process of building perceptions about adolescent offenders and the ways in which gender inequalities are produced, emphasizing the stereotypes that reinforce systems of oppression; the impact of the perceptions built about them on the care policy; and the way in which their lives are made precarious, either individually or collectively, by making their needs invisible or secondary. To illustrate some of the themes highlighted in this analysis, the author selects reports from public agents who interacted with adolescent offenders in the only female detention center in the state of Rio de Janeiro in 2019, based on interviews conducted in research under her coordination.