Given the relationship between overweight and obesity (OV/OB) and poor oral health in children, paediatric dentists are uniquely positioned to provide educational interventions to children with OV/OB during dental visits. To assess how an educational nutrition intervention delivered by dentists affected dental-nutritional behaviors and body mass index (BMI) percentile in children with OV/OB. Retrospective analysis was performed using data collected on 217 patients with OV/OB aged 6-11 years who received nutritional counseling during dental visits at a Federally Qualified Health Center from September 1, 2021, through September 30, 2022. Data were collected on sociodemographic variables, oral health, and BMI percentile. Participants and their guardians were surveyed to measure the frequency of behaviors related to oral health and weight. Multivariable generalized estimating equations were constructed to determine the effect of the intervention on BMI percentile and reported dental-nutritional behaviors. The intervention had no effect on the BMI percentile (p = .35). There were statistically significant reductions in the reported average number of sugar-sweetened beverages consumed daily (p < .001), reported average daily water intake (p < .001), and the reported frequency of brushing teeth (p < .001), the clinical significance of these reductions remains unclear. Further research is needed to establish the efficacy of behavioral interventions at reducing weight and changing health behaviors.