Food insecurity—lack of access to sufficient food for an active and healthy lifestyle—affects more than 10 million children in the United States. Ample research links food insecurity to hampered child physical, cognitive, and social-emotional development and provides insights for policy. After introducing food insecurity and its measurement, this article summarizes what is known about the effects of food insecurity on child development. It then considers how food insecurity harms children and explores both direct pathways through child health and indirect pathways through parenting and parent well-being. Finally, after reviewing existing policy for reducing food insecurity, we provide suggestions for new policy and policy-targeted research.