Agroecology increasingly has gained scientific and policy recognition as having potential to address environmental and social issues within food production, but concerns have been raised about its implications for food security and nutrition, particularly in low-income countries. This review paper examines recent evidence (1998–2019) for whether agroecological practices can improve human food security and nutrition. A total of 11,771 articles were screened by abstract and title, 275 articles included for a full review, with 56 articles (55 cases) selected. A majority of studies (78%) found evidence of positive outcomes in the use of agroecological practices on food security and nutrition of households in low and middle-income countries. Agroecological practices included crop diversification, intercropping, agroforestry, integrating crop and livestock, and soil management measures. More complex agroecological systems, that included multiple components (e.g., crop diversification, mixed crop-livestock systems and farmer-to-farmer networks) were more likely to have positive food security and nutrition outcomes.