Earlier studies of family psychoeducation and clinical reports on multiple family groups (MFGs) have reported substantial reductions in relapse rates for patients with schizophrenia. These groups offer an expanded social network and thereby may confer a margin of protection against relapse. However, to date, there has not been an empirical trial of this modality. The advent of family psychoeducational and behavioral management strategies provided the basis for an experimental, three-way comparison of psychoeducational MFGs to psychoeducation in a single-family format and to MFGs without psychoeducation, using symptomatic relapse as the outcome criterion. After 4 years, the psychoeducational MFGs were significantly more effective in extending remission than the single-family format, while the MFGs without psychoeducation approximated outcome in the psychoeducational MFGs. The respective relapse rates at 4 years were 50%, 78%, and 57%; MFGs averaged 12.5% and 14% per year. These results point toward an enhanced and independent, long-term therapeutic effect for multiple family groups, when combined with antipsychotic medication and psychoeducation, with especially promising cost-effectiveness.