Objectives: The primary objective of the study was to assess whether the Availability, Responsiveness and Continuity (ARC) organizational intervention improved youth outcomes in community based mental health programs. The second objective was to assess whether programs with more improved organizational social contexts following the 18-month ARC intervention had better youth outcomes than programs with less improved social contexts. Method: Eighteen community mental health programs that serve youth between the ages of 5 and 18 were randomly assigned to ARC or control conditions. Clinicians (n = 154) in the participating programs completed the Organizational Social Context (OSC) measure at baseline and following the 18-month ARC organizational intervention. Caregivers of 393 youth who were served by the 18 programs (9 in ARC and 9 in control) completed the Shortform Assessment for Children (SAC) once a month for six months beginning at intake. Results: Hierarchical linear models (HLM) analyses indicated that youth outcomes were significantly better in the programs that completed the 18 month ARC intervention. HLM analyses also showed that youth outcomes were best in the programs with the most improved organizational social contexts following the 18 month ARC intervention. Conclusions: Youth outcomes in community mental health programs can be improved with the ARC organizational intervention and outcomes are best in programs that make the most improvements in organizational social context. The relationships linking ARC, organizational social context, and youth outcomes suggest that service improvement efforts will be more successful if those efforts include strategies to improve the organizational social contexts in which the services are embedded. (Contains 3 figures.)