:Objective:This study examines relations between food insecurity, inhibitory control, and body mass index (BMI) in early childhood.Method:The sample comes from an evaluation of a state-funded prekindergarten program and includes 126 children (mean age = 4.73 yrs, female = 42%) from families with low incomes. Parents reported on their child's food insecurity. Child inhibitory control was assessed using a performance-based task, and children's height and weight were objectively collected at the same time as the inhibitory control assessment. A regression model was used to test whether inhibitory control moderated the association between food insecurity and BMI. The model included a large battery of covariates and adjusted for clustering at the classroom level. Ad hoc analyses were conducted to examine the robustness of findings to different conceptualizations of food insecurity based on the US Department of Agriculture's categories for severity.Results:A significant interaction revealed that inhibitory control moderated the association between food insecurity and children's BMI percentile. Investigation of the simple slopes suggested that greater food insecurity was related to a higher BMI percentile among children who demonstrated stronger inhibitory control. In addition, results from ad hoc analyses examining categories of food insecurity indicated that experiencing very low food security was also related to a higher BMI among children with average and strong inhibitory control.Conclusion:This study makes a unique contribution to the existing literature by examining relations among food insecurity, inhibitory control, and BMI during a critical period in children's physical and brain development. Findings have implications for public health efforts to address childhood obesity among populations with low incomes.