BACKGROUND: Children in US immigrant families experience high rates of food insecurity. Participation in federal child nutrition assistance programs can reduce food insecurity. What remains unknown is whether there are disparities in the participation in these programs among immigrant families based on the length of US residency (LOR). This is an important knowledge gap because there are multiple potential pathways between LOR and common barriers to accessing federal child nutrition assistance programs. OBJECTIVE: To determine the association between LOR and participation in federal child nutrition assistance programs among low-income immigrant families in the United States. DESIGN: Cross-sectional analysis. PARTICIPANTS/SETTING: Nationally representative data from the 2019-2022 National Health Interview Survey. The National Health Interview Survey contains information about participation in federal child nutrition assistance programs, including the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC), and school meal programs, including the National School Lunch Program (NSLP) and the School Breakfast Program (SBP). There were 3488 potentially eligible immigrant families for WIC and 2426 unequivocally eligible immigrant families for NSLP/SBP, according to each program's eligibility criteria, such as income and age. MAIN OUTCOME MEASURES: Participation in WIC and NSLP/SBP. STATISTICAL ANALYSIS: Two weighted multivariable logistic regression models were developed to determine the association between LOR and participation in WIC and NSLP/SBP. LOR was categorized into <
5 years and ≥5 years. Analysis was adjusted for other important risk factors. RESULTS: Results suggest that immigrant families with an LOR ≥5 years were less likely to use WIC (adjusted odds ratio, 0.59
95% CI, 0.42 to 0.84) compared with those with an LOR <
5 years. No association was found between LOR and participation in NSLP/SBP. CONCLUSIONS: Future research should investigate barriers in accessing WIC and whether the nature of barriers differs by LOR. This information can inform interventions to support families in accessing this source of nutritious food.