The Supplemental Nutrition Assistance Program (SNAP) is the largest nutritional assistance program addressing food insecurity in the United States. Due to the program’s reach, SNAP has been called upon to address other nutrition-related challenges facing low-income Americans, including childhood obesity. This study considers the effect of SNAP participation on child weight outcomes after controlling for household financial stress, an important determinant of child overweight status that disproportionately affects low-income households. Using data from the Survey of Household Finances and Childhood Obesity and instrumental variable methods, we find that SNAP participation is negatively associated with obesity among eligible children.