Amid increased concerns about the adverse consequences of low health literacy, it remains unclear how health literacy affects health status and health service utilization. Moreover, studies have shown significant variation in individual adaptation to health literacy problems. This article proposes research hypotheses to address two questions: (1) What are the causal pathways or intermediate steps that link low health literacy to poor health status and high utilization of expensive services such as hospitalization and emergency care? (2) What impact does social support have on the relationships between health literacy and health service utilization? Empirical studies of health literacy are reviewed to indicate the limitations of current literature and to highlight the importance of the proposed research agenda. In particular, we note the individualistic premise of current literature in which individuals are treated as isolated and passive actors. Thus, low health literacy is considered simply as an individual trait independent of support and resources in an individual's social environment. To remedy this, research needs to take into account social support that people can draw on when problems arise due to their health literacy limitations. Examination of the proposed agenda will make two main contributions. First, we will gain a better understanding of the causal effects of health literacy and identify missing links in the delivery of care for patients with low health literacy. Second, if social support buffers the adverse effects of low health literacy, more effective interventions can be designed to address differences in individuals' social support system in addition to individual differences in reading and comprehension. More targeted and more cost-efficient efforts could also be taken to identify and reach those who not only have low health literacy but also lack the resources and support to bridge the unmet literacy demands of their health conditions.