We conducted a review and meta-analyses of 24 studies to evaluate and compare the outcomes of two widely disseminated parenting interventions—Parent-Child Interaction Therapy and Triple P-Positive Parenting Program. Participants in all studies were caregivers and 3- to 12-year-old children. In general, our analyses revealed positive effects of both interventions, but effects varied depending on intervention length, components, and source of outcome data. Both interventions reduced parent-reported child behavior and parenting problems. The effect sizes for PCIT were large when outcomes of child and parent behaviors were assessed with parent-report, with the exclusion of Abbreviated PCIT, which had moderate effect sizes. All forms of Triple P had moderate to large effects when outcomes were parent-reported child behaviors and parenting, with the exception of Media Triple P, which had small effects. PCIT and an enhanced version of Triple P were associated with improvements in observed child behaviors. These findings provide information about the relative efficacy of two programs that have received substantial funding in the USA and Australia, and findings should assist in making decisions about allocations of funding and dissemination of these parenting interventions in the future.