This study evaluated the effectiveness of augmenting a youth suicide-preventive intervention with a brief, home-based parent program. A total of 615 high school youth and their parents participated. Three suicide prevention protocols, a youth intervention, a parent intervention, and a combination of youth and parent intervention, were compared with an "intervention as usual" (IAU) group. All groups experienced a decline in risk factors and an increase in protective factors during the intervention period, and sustained these improvements over 15 months. Results reveal that the youth intervention and combined youth and parent intervention produced significantly greater reductions in suicide risk factors and increases in protective factors than IAU comparison group.