Abstract: Suicide is an acute crisis among US Veterans. Lack of social connectedness is a risk factor for suicidal behavior (SB). Neuroimaging research has shown alterations in brain regions associated with social affiliation, including the anterior cingulate cortex (ACC), to be implicated in psychiatric disorders that increase risk for suicide. The current study examined the relationship between reduced social connectedness and functional connectivity of the ACC in a sample of Veterans with a history of SB.