Social isolation and disability are established risk factors for poor nutrition. We aimed to assess whether social isolation is associated with diet quality specifically among adults with disabilities.This cross-sectional analysis used data from the National Health and Nutrition Examination Survey, 2013–2018. Adults with a disability, who were not pregnant, breastfeeding, or missing dietary intake data were included (n = 5,167). Disability was defined as a physical functioning limitation based on difficulty with any activities of daily living, instrumental activities of daily living, lower extremity mobility activities, or general physical activities. The Healthy Eating Index (HEI)-2015 measured diet quality; higher scores correspond to higher diet quality. We computed a social isolation index by summing single status, living alone, and two social engagement difficulty measures (one point for each component met; maximum 4 points). Multivariable linear regression, controlling for demographic and health covariates, estimated differences in HEI scores for dietary intake data, by social isolation score.Over half of HEI scores were