The protective influence of social relationships on health is widely documented; however, not all relationships are positive, and negative aspects of relationships may be detrimental. Much less is known about the relationships characterized by both positivity and negativity (i.e., ambivalence). This article provides a theoretical framework for considering the influence of ambivalent relationships on physical health, including reasons why ambivalence should be considered separately from relationships characterized as primarily positive (supportive) or primarily negative (aversive). We introduce the social ambivalence and disease (SAD) model as a guide to understanding the social psychological antecedents, processes, and consequences of ambivalent relationships. We conclude by highlighting gaps in the literature and features of the SAD model that may serve as a guide to future research on potential health-relevant pathways of ambivalent relationships.