Food insecurity (FI) is one of the major causes of malnutrition and is associated with a range of negative health outcomes in low and middle-income countries. The burden of FI in southern Africa is unknown, although FI continues to be a major public health problem across sub-Saharan Africa as a whole. Therefore, this review sought to identify empirical studies that related FI to health outcomes among adults in southern Africa. Altogether, 14 publications using diverse measures of FI were reviewed. The majority of the studies measured FI using modified versions of the United States Department of Agriculture Household Food Security Survey Module. A wide range in prevalence and severity of FI was reported (18–91%), depending on the measurement tool and population under investigation. Furthermore, FI was mostly associated with hypertension, diabetes, anxiety, depression and increased risk of human immunodeficiency virus (HIV) acquisition. Based on the findings, future research is needed, especially in countries with as yet no empirical studies on the subject, to identify and standardize measures of FI suitable for the southern African context and to inform public health policies and appropriate interventions aiming to alleviate FI and potentially improve health outcomes in the region.