Nutrition security, an emerging concept distinct from and complementary to food security, has gained increasing interest as a focus of efforts to reduce hunger, improve nutrition, and prevent diet-related health conditions. Yet, unlike food security, which has well-established measures, nutrition security lacks standardized measures for assessment. This gap hinders the ability to evaluate progress in improving nutrition security both in the United States and globally. In September 2024, a workshop to explore how to measure nutrition security was hosted by the U.S. Department of Agriculture (USDA) Economic Research Service (ERS), in collaboration with the Southern University Agricultural Science Center of Excellence for Nutrition and Diet (ASCEND) Nutrition Hub. A recent conceptual framework proposes that nutrition security includes the two constructs of healthy diets and nutritional status, but consensus on that framework and on measurement is lacking. Various measures of nutrition security have been proposed, each with different methods, feasibility, cost, and data requirements. With consensus yet to emerge on the conceptualization and measurement of nutrition security, further research is needed to validate proposed conceptual frameworks, refine measurement methods and measures, assess their validity, and determine their utility for monitoring nutrition security at the population level. This research will advance efforts to improve nutrition security and inform nutrition policy and program interventions.