In this study, we base on Bronfenbrenner’s bioecological model and propose to examine health behaviours of adolescents – girls and boys – in light of the Person-Context transactions. More precisely, we consider as a special issue the relations between health and degraded contextual Person-Family and/or Person-School transactions. One thousand and six French middle-school (8th grade) adolescents, 479 boys and 527 girls, took part in this study. They were categorized into four groups: Family disconnected adolescents, School disconnected adolescents, Double disconnected adolescents (that is, adolescents who are disconnected to both contexts), and Not disconnected adolescents (that is, adolescents disconnected neither to Family nor to School). The Duke Health Profile was used and three of its health measures were considered: self-esteem, anxiety, and depression. The results show that (1) the girls have more unfavourable scores of self-esteem, anxiety, and depression than the boys, (2) the girls or the boys who experience a situation of contextual disconnection (Family disconnection, School disconnection, or Double disconnection) exhibit more unfavourable health scores than the Not disconnected ones and (3) a Double disconnection amplifies the risks of health disorders. Moreover, the Family disconnected adolescents exhibit more unfavourable health scores than the School disconnected ones. Furthermore, the amplification effect, that appears when the adolescents experience a situation of Double disconnection, differs as a function of both adolescents’ gender and health outcomes. These two last results outline a complex dynamic in which the relations between contextual disconnection and health are modulated by gender.