Smith-Magenis syndrome (SMS) is a complex disorder characterized by numerous challenges, including intellectual disability, speech delay, decreased pain sensitivity, sleep disturbances, hyperactivity, mood instability, and self-injury. Caregivers must readily adapt to the ever-changing needs of the child. Due to these demands, caregivers may encounter difficulties maintaining their own level of well-being. Thus, a total of 112 primary caregivers (i.e., parents) of individuals diagnosed with SMS responded to online questionnaires to assess demographic and psychosocial factors, such as perceptions of child health vulnerability, benefit finding, sleep behaviors, anxiety and depression symptomatology, and caregiver satisfaction and self-efficacy, which may be related to caregiver well-being. Results show that, among mothers, caregiver well-being was directly related to perceived child health vulnerability, caregiver satisfaction, and benefit finding, and a significant moderating effect was observed for depression/anxiety counseling after beginning the caregiver role on the relationship between anxiety symptomatology and caregiver well-being. Results further suggest that maternal caregivers who report high levels of anxiety but do not seek counseling fair the worst in terms of well-being. Among fathers, lower depression symptoms and greater benefit finding were related to higher levels of caregiver well-being. These data show that many factors play roles in influencing coping and well-being among SMS caregivers. Investigating these variables and relationships may reveal additional resources and interventions to assist primary caregivers.