Food insecurity is experienced by millions of Americans, and its prevalence has increased dramatically in recent years. Due to its prevalence and many demonstrated negative health consequences, food insecurity is one of the most important nutrition-related public health issues in the U.S. In this article, we cover how economic insights and models have improved our understanding of the determinants of food insecurity, the effects of food insecurity on health outcomes, and the impact of food assistance programs on food insecurity. We conclude with a discussion of several issues where economists can provide further insights.