Suicide rates within the U.S. military are elevated. The interpersonal theory of suicide, supported within military samples, suggests that social disconnectedness confers risk for suicide. Autism spectrum disorder (ASD) is characterized by symptoms-difficulties in social communication/interaction (SCI) and restricted and repetitive behaviors (RRBs)-that contribute to social disconnectedness. To our knowledge, no study has examined ASD-related traits and suicide risk among active duty U.S. military service members. Participants included 292 active duty U.S. military service members ( age = 28.67 [7.40] years, 68.5% male, 78.1% White). The Autism Spectrum Quotient, Repetitive Behaviours Questionnaire-2 for Adults, Self-Injurious Thoughts and Behaviors Interview-Short Form, and Interpersonal Needs Questionnaire assessed for SCI difficulties, RRBs, suicidal symptoms, and interpersonal theory of suicide constructs (i.e., perceived burdensomeness, thwarted belongingness), respectively. Elevated levels of SCI difficulties and RRBs were associated with increased odds of reporting suicidal thoughts and behaviors occurring since joining the military, controlling for the number of years of service and suicidal symptoms occurring prior to joining the military. Perceived burdensomeness and thwarted belongingness statistically accounted for the relationship between ASD-related traits and suicidal ideation occurring since joining the military; a rival mediator, emotion dysregulation, was not a significant mediator. Among active duty U.S. military service members, greater ASD-related traits were associated with an increased likelihood of reporting suicidal thoughts and behaviors occurring since joining the military. Clinical efforts targeting perceived burdensomeness and thwarted belongingness might reduce suicide risk among military service members with elevated ASD-related traits. (PsycINFO Database Record (c) 2020 APA, all rights reserved).