A large body of research built over the last few decades examines the interaction between stressful events and vulnerability traits to explain how a person becomes suicidal. This stress-diathesis model has been extremely fruitful to improve our understanding of suicidal behavior, but recent findings suggest that interactions could be more complex than expected. Indeed, environmental insults during pregnancy, childhood, or adolescence induce neurodevelopmental changes that increase the vulnerability for suicidal behavior in later life. In this chapter, we will outline the significance of recent neurodevelopmental findings for the stress-vulnerability factors of suicidal behavior. The coherence and applicability of an integrative neurodevelopmental model of suicidal behavior will be discussed in the light of current research concerning genetics, neuroimaging, and neuropsychology, and the new classification systems.