Telehealth interventions have the opportunity to scale evidenced-based therapeutics and increase service access to historically hard to reach populations, including rural, and minority groups. Behavior management parenting interventions are a best-practice intervention to treat a range of disruptive behavior disorders and family dysfunction concerns, which have traditionally occurred in person, but recently been trialed online due to growing demand and a need for remote delivery during COVID-19. There is limited and mixed information to date regarding evidence for online services and minimal research on client and therapeutic factors associated with better outcomes, which is critical for advancing efficacy in the rapidly-growing approach to treating child mental illness. Therefore, we conducted a systematic review and meta-analysis (k = 24, total number of intervention participants = 1469 and control participants = 800) of the impact of digital parent training interventions on parent skill, parent mental health, and child externalizing mental health outcomes from 2000 to 2020, among children 2-12 years old, across four databases. Exclusionary criteria include programs targeted for parents of children with intellectual disabilities, autism, brain injury, nutrition/health/dental needs or primary medical diagnosis. Across outcomes, there was a modest effect size of digital parent training interventions (g =.22-.30), compared to controls using random effect two-level and multi-level models. Study heterogeneity varied across outcomes (I² = 18.6% to 66.3%). Results of publication bias were mixed across tests, but they were suggestive of a slight inflation of the effects sizes across outcomes. We tested several moderators related to child demographics, family socioeconomic status, intervention design, and risk of bias. We found the effects of digital parent training on parent skills and child outcomes were stronger if the intervention used was evidence-based, combined hybrid interactive platforms with a therapist and was compared to an inactive control. Given the limitations from the existing literature assess moderating effects regarding population characteristics (i.e. SES, parent mental health), we call on future studies to provide standardized demographics to aide future knowledge synthesis work and provide templates for shared measurement. We preregistered our meta-analysis here, with datafile, code and supplementary: https://osf.io/e35bt/.