<h3>Objective(s)</h3> To evaluate efficacy of health promotion and obesity prevention interventions among children and adolescents with DD. <h3>Data Sources</h3> Databases searched: PubMed, CINAHL, PsycINFO, Cochrane Library, Psychology and Behavioral Sciences Collection, Health Source: Nursing/Academic, Web of Science, Embase, and Scopus. Search terms: child*, adolesc*, pediatric*, disability, intellectual*, impair*, development*, autis*, down syndrome*, cognitive*; health promotion, healthy lifestyle, healthy eating, obesity intervention, obesity prevention, physical exercise; BMI, eating behaviors, physical in/activity, dietary intake, and sedentary behaviors. <h3>Study Selection</h3> Inclusion criteria: (1) children and adolescents (6-17 years) with DD (2) interventions targeting obesity outcomes within a child's natural environment; (3) peer-reviewed, experimental or quasi-experimental studies; (4) quantitative or mixed methods approach; (5) reported primary outcomes for the child; (6) published between 2010 – 2021. Reviewers worked in pairs to independently screen articles. Author and journal information was blinded. Selection was based on consensus. Average interrater reliability across screeners was high (92.7%). Of 21,889 unique records, 21 studies met selection criteria. <h3>Data Extraction</h3> Data Extraction was conducted by six research team members who worked in three pairs using a standardized form adapted from existing sources. We adapted Reichow's (2011) evaluative method for rating the rigor of each study and determining the overall level of evidence for each intervention. Interrater reliability for rating of rigor was 88%. Rating disagreements within pairs were resolved through discussion. <h3>Data Synthesis</h3> Interventions were categorized into five categories including: aerobic and strength training, sport-based physical activity, aquatic exercise, active video gaming, and diet and lifestyle interventions. None of the intervention categories met the recommended threshold for ‘established' EBP. Aquatic exercise programs and active videogaming programs approached Reichow's (2011) cut off for ‘probable EBP'. Diet and lifestyle interventions, aerobic and strength training exercise programs, and sports-based physical activity programs warranted an overall rating of ‘not an EBP'. <h3>Conclusions</h3> Interventions such as sports-based exercise programs and active video gaming showed promise, but more research is needed to confirm their effectiveness. Future research must focus on theoretically grounded and rigorous intervention studies with diverse samples. <h3>Author(s) Disclosures</h3> None