In this state-of-the-science review, we summarize the key constructs and concepts within the interpersonal theory of suicide. The state of the scientific evidence regarding the theory is equivocal, and we explore the reasons for and some consequences of that equivocal state. Our particular philosophy of science includes criteria such as explanatory reach and pragmatic utility, among others, in addition to the important criterion of predictive validity. Across criteria, the interpersonal theory fares reasonably well, but it is also true that it struggles somewhat-as does every other theory of suicidality-with stringent versions of predictive validity. We explore in some depth the implications of the theory and its status regarding people who are minoritized. Some implications and future directions for research are also presented.