Suicide is a major public health crisis, particularly among America’s youth. Increasing evidence suggests that living with a neurodevelopmental disorder increases the risk of suicidal thoughts and behaviors. In this chapter, we first review the epidemiology and known psychology of suicidal thoughts and behaviors, with an emphasis on individuals with neurodevelopmental disabilities. Next, we discuss means for identifying suicide risk through screening, particularly when disabilities affect cognition and communication. We review the literature on known pathophysiology and biomarkers of suicide. Finally, we conclude by providing resources to help make evidence-informed decisions about management in the setting of a concern for impending suicidal behavior.