This study examined the efficacy of a self-administered behavioral family intervention for 126 parents of toddlers. The effects of 2 different levels of intensity of the self-administered intervention were contrasted (self-administered alone or self-administered plus brief therapist telephone assistance). The results provide support for the efficacy of the self-administered form of behavioral family intervention. There were significant short-term reductions in reported child behavior problems and improvements in maternal parenting style, parenting confidence, and anger. Families who received minimal therapist assistance made more clinically significant gains compared with families who completed the program with no therapist assistance. The intervention effects were maintained at 6-month follow-up. The implications of the findings for the population-level delivery of behavioral family interventions are discussed.