Unmet social needs--including food, housing, and utilities--have been associated with negative health outcomes, but most prior research has examined the health associations with a single unmet need or analyzed samples that were homogeneous along one or more dimensions (e.g., older adults or patients with chronic health conditions). We examined the association between unmet social needs and psychosocial and health-related outcomes in a sample of Medicaid beneficiaries from 35 U.S. states. In 2016-2017, 1,214 people completed an online survey about social needs, demographics, and health-related and psychosocial outcomes. Seven items assessing social needs formed an index in which higher scores indicated higher levels of unmet needs. Participants were eligible if they were =18 years and had Medicaid. The sample was predominantly female (87%). Most (71%) lived with at least one child =18 years, and 49% were White and 33% were African American. Average age was 36 years (SD = 13). The most common unmet needs were not enough money for unexpected expenses (54%) and not enough space in the home (25%). Analyses controlling for recruitment method and demographics showed that increasing levels of unmet social needs were positively associated with stress, smoking, and number of chronic conditions, and negatively associated with future orientation, attitudes toward prevention, days of exercise/week, servings of fruits or vegetables/day, and self-rated health (all p < 0.01). Results add to the evidence about the relationship between unmet social needs and health. Interventions to help meet social needs may help low-income people improve both their economic situations and their health.