Food insecurity is a significant problem in the developing world, and one that is likely to increase given the current global food crisis spurred by rising oil prices, conversion of food to biofuels, and reduced harvests in the wake of natural disasters. The impacts of food insecurity on nutrition status, growth, and development are well substantiated; less is known about the non-nutritional impacts of food insecurity, such as its effects on mental health. This systematic review assesses current findings regarding the impacts of food insecurity on mental health in developing countries. Both qualitative and quantitative studies are considered. The results of the search reveal that little work has examined these issues directly, and serious methodological flaws are present in many of the existing studies. Gaps in the literature, implications, and research priorities are discussed.