Food insecurity is detrimental to children’s well-being. A better understanding of factors contributing to low and very low food security among children in the United States can guide the design of food assistance programs. We analyze the effects of household characteristics and local food environment attributes, including food prices and availability of food stores and eating places, on children’s food insecurity. We also investigate the effects of these characteristics and attributes on food preparation time. Using Becker’s household production approach, we propose an economic model that formalizes the use of constrained financial and time resources in the household. The model motivates empirical specifications of food insecurity and food preparation time equations, which are estimated jointly by maximum likelihood. We assemble a large dataset of households with children by pooling across years and matching the Food Security Supplement of the Current Population Survey, 2002–2010, and the American Time Use Survey, 2003–2011. These data are supplemented with location-specific variables from several large national sources. The estimates suggest intuitively plausible effects of demographic and socioeconomic characteristics on food insecurity and food preparation time. They also indicate that residing in a location with higher fast food prices and with fewer convenience stores and specialty food stores tends to exacerbate food insecurity. Public policies supporting parents’ financial, transportation, and childcare needs, enhancing parents’ resource management skills, supporting the food needs of school-age children, and encouraging businesses to open specialty food stores in poorer neighborhoods can help alleviate very low food security among children.