© 2019, Springer Science+Business Media, LLC, part of Springer Nature. Although autism spectrum disorder (ASD) is associated with significant mental health concerns, little is known about suicidality, particularly among youth. To address this critical gap in the literature, the current study examined the predictive validity of (1) demographics, (2) core autism symptoms, (3) cognitive abilities and adaptive behavior, (4) comorbid psychopathology, and (5) medical problems, for suicide-related behaviors among autistic youth (N = 481; Mage = 11.56 years). As indices of suicide-related behaviors, parents reported on whether the child had ever (1) talked about killing themselves, and (2) engaged in deliberate self-harm or attempted suicide. These two suicide-related outcomes had distinct clinical correlates, including child age, parental education, restricted and repetitive behaviors, IQ and adaptive behavior, affective and conduct problems, and medical concerns.