Background: A growing number of studies are emphasizing the importance of positive and negative appraisals of caregiving and the utilization of social resources to buffer the negative effects of caring for persons with dementia. By assessing the roles of unmet needs and formal support, this study tested a hypothesized model for Korean family caregivers’ satisfaction and burden in providing care for persons with dementia. Methods: The stress process model and a two-factor model were used as the conceptual framework for this study. Data for 320 family caregivers from a large cross-sectional survey, the Seoul Dementia Management study, were analyzed using structural equation modeling. In the hypothesized model, the exogenous variables were patient symptoms, including cognitive impairment, behavioral problems, and dependency on others to help with activities of daily living and with instrumental activities of daily living. The endogenous variables were the caregiver's perception of the unmet needs of the patient, formal support, caregiving satisfaction, and caregiving burden. Results: The adjusted model explained the mediating effect of unmet needs on the relationship between patient symptoms or formal support and caregiving satisfaction. Formal support also had a mediating effect on the relationship between patient symptoms and unmet needs. Patient symptoms and caregiving satisfaction had a significant direct effect on caregiving burden. Conclusion: The level of unmet needs of persons with dementia and their family caregivers must be considered in the development of support programs focused on improving caregiving satisfaction.