Nutrition security is challenging in regions where resources are limited and food production is naturally constrained. In low- and middle-income countries (LMICs), undernutrition is high for many reasons, including lack of nutritional diversity and low high-quality protein content. Interest in the role of animal-source food (ASF) in reducing nutrition insecurity is increasing, as evidence from LMICs suggests that consumption of ASF is strongly associated with reduction in stunting, improved diet quality, and overall nutrition, particularly in early stages of life. We review the strengths and limitations of ASF consumption in terms of accessibility, safety, and nutritional benefits compared to non-ASF sources. We present a critical discussion on existing barriers to ASF consumption and its future directions in LMICs. Understanding the role of ASF in improving nutrition security in LMICs is crucial to optimizing public health, designing appropriate interventions, and implementing effective policy in resource-poor settings.