Computer-mediated health communication (CMHC) has increasingly played a role in connecting individuals across the globe to health information and online support groups. For individuals living with a rare disease, and their caregivers, CMHC can serve as a critical tool for social support and information seeking, while addressing feelings of isolation due to the low prevalence of living with a rare disease. Over the past two decades, there has been an increase in scholarship surrounding CMHC and social support. However, scholarship within the context of CMHC in rare diseases has only increased within the past few years and lacks an explicit connection to important theoretical constructs in both communication and public health. Thus, this dissertation aims to explore the intersection of CMHC, interpersonal communication, and social support among caregivers who use Facebook groups as a CMHC tool for Lennox-Gastaut Syndrome, a rare, catastrophic epilepsy syndrome. Long-standing communication theories, including social penetration theory and communication privacy management, guide the theoretical framework for this dissertation while theoretical constructs from public health, including social support and health literacy are addressed.