ABSTRACT The older (aged 50 or above) never-married (ONM) population is diverse and has been growing rapidly. Its growth poses pressing and complex challenges for aging, age-related diseases, health care, and long-term care. However, this population remains severely understudied. Their health remains a contested issue, with social networks central to the discussion. Two conceptual models (deficits versus resilience) have competing predictions. Although many studies document ONM adults’ health and network disadvantages, they overlook ONM adults’ diversity in sociodemographic backgrounds, socioeconomic status, and singlehood pathways. The heterogeneous features and impacts of social networks within ONM adults are complex and require rigorous investigation. The little research on ONM adults is largely due to data limitations. Population-based surveys of older adults have small never-married sample sizes and/or limited measurement of social networks and single life, leading to incomplete network mapping, insufficient network theory testing, underpowered analyses, and an inability to consider the ONM’s diversity. To address these critical gaps, we propose data collection, analysis, and dissemination of the first National Study of the ONM Adults (NSONMA). In partnership with Gallup, we will collect the first-ever nationally representative survey data on ONM adults across two waves. We will examine the role of social networks in the etiology of health risk behaviors and health in the ONM population, identify the intra- and interpersonal mechanisms underlying the role of social networks, and detect subgroup differences therein.