Despite increasing prevention efforts, military suicide rates have surpassed those of the general population. This trend may reflect a deficit in our understanding of suicide, historically atheoretical and based on decreasing risk factors of suicide. The interpersonal–psychological theory of suicide (IPTS) provides a theoretical foundation to understand suicide but only assesses three risk factors of suicide and is primarily aimed at explaining who may die by suicide, but not when. The fluid vulnerability theory (FVT) provides a broad theoretical framework to understand and organize risk and protective factors of suicide in order to understand the process of suicide risk over time. Overlaying the IPTS’s constructs of thwarted belongingness, perceived burdensomeness, and the acquired capability for suicide within the FVT framework provides a robust model to understand not only who is at risk for suicide but also when suicide risk is likely to emerge.