Health anxiety is a multidimensional construct referring to worry about health, reassurance seeking, hypervigilance to bodily sensations, and beliefs that health concerns are not taken seriously by others. Research suggests health anxiety can be triggered by a diagnosis of a health condition such as breast cancer. Social factors are postulated to be involved in the occurrence and maintenance of health anxiety, but little empirical evidence is available in this area. The present study tested the role of perceived adequacy of social support and unsupportive social interactions in health anxiety relative to general anxiety, depression, and demographic/cancer-related variables. Canadian women diagnosed with early stage breast cancer within the last 10 years (N 131) completed a web-based survey. Social factors contributed to significant variance in health anxiety and its 4 dimensions, even after taking other variables into account. The results underscore the importance of social support to health anxiety and highlight a need to assess social factors when assessing and treating health anxiety in this population.