Lack of social ties, or social disconnectedness is known to be associated with worse mental health outcomes. Social disconnectedness manifests in different forms, such as living alone, having a small social network, or feelings of loneliness. Despite overlapping characteristics, the conditions are distinctly different from each other. How different forms of social disconnectedness are combined to influence mental health is an underexplored question in the literature. In this paper, we examine the associations between three forms of social disconnectedness (social isolation, loneliness, and living alone) and subjective well-being (life satisfaction and depressive symptoms) among older adults in rural China. Using a longitudinal study of older adults in Anhui Province, China (2015–2018), we examine the independent, additive, and interactive effects of the three forms of social disconnectedness on subjective well-being. We find that those who are exposed to all three forms of social disconnectedness suffer from the highest depressive symptoms and lowest life satisfaction. Moreover, the different combinations of social disconnectedness affect older adults’ subjective well-being in diverse ways. The adverse effects of social disconnectedness on subjective well-being are found to be stronger for women than for men. The results underscore the necessity for targeted policy intervention for subpopulations with differential needs.