Purpose: The purpose of this study was to provide the comprehensive factors affecting the sleep quality in family caregivers of patients with dementia in South Korea, including patient and caregiver-related factors. Methods: The participant were a total of 156 family caregivers who live with patients with dementia in South Korea. Patient and caregiver-related factors were measured using tools with high reliability. Data collection was performed from May to August 2019, and data were analyzed using descriptive analysis, t-test, ANOVA, Pearson's correlation coefficients, and multiple regression with the SPSS/21.0 program. Results: The significant factors affecting family caregivers’ sleep quality were their depression (β=.52, p<.001) and their education (β=.23, p=.019). Conclusion: There is a need to monitor caregivers’ depression and sleep quality. Future studies, biomarker to monitor caregivers’ sleep quality to achieve objective evidence. There is a need to provide additional education programs to improve the understanding around caregivers' sleep quality especially for caregivers with low level of education.