 This systematic review aimed to determine the quality, efficacy and theoretical application of digital interventions designed to improve physical activity, PA, in preschool-aged children. The study identified eight studies that met the inclusion criteria, with only two studies receiving an overall rating of strong quality and low risk of bias. All but one study had a small sample size, and positive and significant changes in child PA outcomes were reported in only two studies with weak overall quality. No patterns of effectiveness were identified based on the application of theory, and no studies reported on implementation outcomes such as adoption, cost, penetration, or sustainability. The interventions with a significant effect on PA use child-centered activities, while parent-directed digital interventions alone were ineffective for improving PA, future research with rigorous designs, monitoring of implementation outcomes, and testing of the contributions of digital components will advance understanding of the effectiveness of digital interventions for increasing PA in children. This article was authored by Terence Swindle, Anvesh Bipasala, Nan Zeng, and others. We are article.tv, links in the description below.