Advances in genomic research are increasingly identifying genetic components in major health and mental health disorders. This article presents a Family System Genetic Illness model to address the psychosocial challenges of genomic conditions for patients and their families, and to help organize this complex biopsychosocial landscape for clinical practice and research. This model clusters genomic disorders based on key characteristics that define types of disorders with similar patterns of psychosocial demands over time. Key disease variables include the likelihood of developing a disorder based on specific genetic mutations, overall clinical severity, timing of clinical onset in the life cycle, and whether effective treatment interventions exist to alter disease onset and/or progression. For disorders in which carrier, predictive, or presymptomatic testing is available, core nonsymptomatic time phases with salient developmental challenges are described pre- and post-testing, including a long-term adaptation phase. The FSGI model builds on Rolland's Family System Illness model, which identifies psychosocial types and phases of chronic disorders after clinical onset. The FSGI model is designed to be flexible and responsive to future discoveries in genomic research. Its utility is discussed for research, preventive screening, family assessment, treatment planning, and service delivery in a wide range of healthcare settings.