Research on relationship aspects in residential treatment of criminal young persons has largely been neglected despite the general finding in treatment research that such aspects have a large bearing on outcome. In this article, two studies of associations between relationship aspects and outcome in this treatment context are presented. In one of them, two treatment units practicing Aggression Replacement Training and CBT-techniques and 2 U with more conventional, relationally oriented treatment approaches were studied using process questionnaires and interviews. In the other study, adolescents who had been sentenced to treatment were interviewed about treatment experiences 1 year after release. Despite considerable attrition, several interesting findings were noted: The boys' alliance ratings were associated with the collaborative aspect of the staff's alliance ratings, but not with the bond aspect, warm and close staff feelings were related to negative outcome and the boys' conceptions of the treatment model but not of the relationship with the staff was associated with positive outcome. The results suggest that a distinction should be made between a mutual bond aspect of the staff-boy relationship that was not related to outcome and a collaborative aspect which was related to outcome. © 2007 Springer Science+Business Media, LLC.