The client–therapist relationship is recognized as an important factor contributing to outcomes of child and youth care. Particularly in secure residential youth care, in which adolescents with mainly externalizing behaviour problems are often placed coercively, the client–staff relationship seems to be important for the achievement of positive outcomes. The present study aims to assess the client–staff relationship for a group of 135 adolescents in secure residential care and factors associated with a positive relationship. The results show that adolescents, group care workers and teachers experience a limited affective bond in their relationship 2 months after the adolescents were admitted to the secure care centre. Adolescents do tend to use care workers and teachers as a secure attachment figure, which suggests that an affective bond is no precondition for the adolescents to experience staff as a secure base. Main predictors of a good relationship are the positive treatment skills of both group care workers and teachers. These findings point to the need for training of care workers and teachers so that they are better prepared for working with these adolescents.