Better Beginnings, Better Futures is a large-scale, multi-year, longitudinal research-demonstration project designed to reduce children's problems, promote healthy child development, and enhance family and community environments in three economically disadvantaged communities in the province of Ontario, Canada. The initial intervention was implemented from 1993 to 1997 and focused on families with children from 4 to 8 years of age in their first 4 years of schooling (from Junior Kindergarten to Grade 2). This study examined the long-term parent, family and community programme outcomes, 15 years after the start of the intervention, when the young people who had participated in the intervention as young children were 18 to 19 years of age. Comparison of intervention communities with matched non-intervention communities showed a mix of outcomes. Although few significant differences between intervention and comparison communities were found with regard to parents' health and family outcomes, there was evidence that parents in the intervention communities were engaging in fewer risk behaviours, had lower levels of depression and had more community involvement than parents in the comparison communities. These results suggest that the intervention did have some positive long-term effects on youths' parents and on their community environments. Results are discussed with respect to the importance of considering family and neighbourhood contexts in the development and evaluation of prevention programmes. Copyright © 2012 John Wiley & Sons, Ltd.