The field of behavioral parent training began in the 1960s and has become one of the predominant empirically based clinical approaches for addressing child behavior problems and developmental delays. Three historical trends spurred the initial development of parent training: concerns about the ineffectiveness of traditional child therapy, the burgeoning growth of behavior modification, and the idea that using parents to deliver mental health services could enhance the effectiveness of therapy. Early parent training research focused on small studies examining the effects of various treatment components and training strategies based on learning principles. Subsequent trends involved the development of standardized intervention models and research on their effectiveness; examinations of generalization; and applications of parent training in areas beyond child disruptive behavior or delayed development. Despite the phenomenal growth of behavioral parent training, research has identified challenges related to parent engagement/dropout, differing responsiveness across diverse cultural and demographic groups, and the need for high quality training and supervision of practitioners. These issues constitute important current and future research directions. This presentation will provide an overview of behavioral parent training research across the decades using illustrative examples and will discuss the implications of this research for practitioners working with children and their families.