Adverse parenting practices, including child maltreatment, interfere with children's adjustment and life outcomes. In this article, Ronald Prinz describes the Triple P--Positive Parenting Program, designed to improve parenting population-wide. Prinz offers four main reasons to take a population approach. First, official records grossly underestimate the extent of problematic parenting. Second, communities need to normalize involvement in parenting support programs rather than singling out or stigmatizing parents. Third, a population approach could have many benefits, such as preventing behavioral and emotional problems in early childhood, encouraging greater school readiness, and reducing the risk of problems during adolescence. Fourth, compared to strategies that target a narrow segment of parents and children, a population approach may create a climate of positive social contagion for positive parenting. Triple P--a multitiered system of programs with varying intensity levels, delivery formats, and specialized variants--aims to increase the number of parents who have the knowledge, skills, and confidence to raise their children well; to decrease the number of children who develop behavioral and emotional problems; and to reduce the number of children maltreated by their parents. Prinz outlines the origins and guiding principles of Triple P, describes the program model, and explains the conceptual framework for the multitiered approach to prevention. He then summarizes the evidence for this approach, emphasizing population studies that have tested the full Triple P system. He also discusses such critical issues as implementation and quality assurance, benefits versus costs, and significant obstacles to adopting a population strategy for parenting support.