A systemic approach to researching families and health should capture the complex network within which family members are embedded, including multiple family relationships and larger systems of health care. However, much of the families and health research focused on adult family members has focused solely on intimate partnerships, usually the marital relationship. This neglects the remainder of the powerfully influencing family relationships adults retain, and may increasingly focus on as they age. We conducted a systematic review of the families and adult health literature, retaining 72 articles which were subsequently thematically coded to highlight main foci of this area of research. Results highlight six themes, which include family relationship quality, family composition, behavioral factors in health and health care, psychophysiological mediators, caregiving, and aging health. Findings support an underrepresentation of family members, other than the intimate partner, in research on adult health.