<h3>Background</h3> Fathers' nutrition knowledge, attitudes and child feeding practices impact children's eating behavior and future weight. There is a need to target fathers in child nutrition education interventions, especially in ethnic groups like Asian Indians (AI). <h3>Objective</h3> The study aimed to examine the efficacy of a social cognitive theory (SCT) based online nutrition education program on determinants of behavior (knowledge, self-efficacy) and behavior (healthy eating, physical activity) in AI fathers and their children. <h3>Study design, Settings, Participants</h3> Ninety-eight AI fathers of 6-11-year-old children from various Indian communities in Florida were recruited to participate in the web-based nutrition education program. Fathers were asked to engage with the intervention for 6 weeks and topics included father's role in child health, ideal child feeding practices, healthy eating and physical activity. Validated survey questionnaires at baseline, post-intervention (6 weeks) and follow up (12 weeks) assessed participants' knowledge, child feeding, self-efficacy, self-regulation, diet and physical activity for fathers and their children. <h3>Analysis</h3> Descriptive statistics and Repeated Measures ANOVA were performed through SPSS v 26. <h3>Results</h3> Majority of AI fathers were between 35-44 years (75.5%). There was a statistically significant increase on the AI fathers' nutrition knowledge (F = 120.93, <i>P</i> < 0.01), self-efficacy (F = 19.980, <i>P</i> < 0.01), self-regulation (F = 10.387, <i>P</i> < 0.01), overall diet quality (F = 12.257, <i>P</i> < 0.01), physical activity (F = 32.790, <i>P</i> < 0.01) and a reduction in restrictive feeding practices (F = 5.683, <i>P</i> = 0.004) through the intervention. Improvements were also noted in father reported child fruit and vegetable intake (F = 30.821, <i>P</i> < 0.01), total fat consumed/day (F = 4.040, <i>P</i> = 0.020) and physical activity minutes (F = 15.018, <i>P</i> < 0.01). <i>Post hoc</i> analyses revealed significant changes between baseline and post-intervention for all 9 outcomes and post-intervention and follow up for AI fathers' diet related self-efficacy and self-regulation scores. <h3>Conclusion</h3> Web-based interventions are effective to improve behavioral determinants and behavior in AI fathers' and their children. Future studies should consider diverse AI father groups for childhood obesity prevention.