Purpose <p>Autism is characterized by high rates of psychiatric co-occurring conditions, including suicidality. Autistic adults report higher suicidal ideation and behavior compared to non-autistic adults. However, the mechanisms underlying these differences are still unclear. Research in non-autistic adults highlighted the role of emotion regulation difficulties in various psychopathologies, including suicidality. The current study examined the role of emotion regulation as a mediator between autism and suicidal ideation.</p> Methods <p>Fifty-one (51) autistic adults (29.41% female, mean age = 24.31, SD = 5.42) with no intellectual disability, and 71 comparable non-autistic adults (40.84% female, mean age = 23.67, SD = 4.63) self-reported on emotion regulation using the Difficulties in Emotion Regulation Scale (DERS) and on suicidal ideation using the Brief Symptoms Inventory (BSI).</p> Results <p>Significantly higher rates of suicidal ideation and difficulties in emotion regulation were reported by autistic, compared to non-autistic, adults. Higher levels of difficulties in emotion regulation were associated with increased suicidal ideation. Difficulties in emotion regulation, lack of emotional clarity, and limited access to emotion regulation strategies fully mediated the association between having autism and suicidal ideation.</p> Conclusion <p>Results suggest that emotion regulation difficulties in general, and particularly the lack of emotional clarity and limited access to emotion regulation strategies, may play a mechanistic role in the increased suicidal ideation of autistic adults. Interventions targeting emotion regulation strategies and emotional clarity may assist in alleviating suicidal ideation in autistic adults.</p>