In the context of an aging population, both the need for home care services and its complexity of care have increased in many high-income countries. Yet, the definition of what constitutes complex care is largely elusive. This systematic review examined the conceptual definition of complex care within the home care environment using several social and health science databases for research published from 2000 to 2017. Of the 25 articles and reports identified, only 16 addressed complex care specifically and included older adults, aging, and/or home care. The results showed that complex care for older adults is primarily defined from a biomedical approach focusing on chronic disease and management and less commonly from the perspective of the social determinants of health. Future studies should consider the importance of the continuum of care needs from both the biomedical and the social determinants to adequately plan and provide care for older adults.