Aim: This study aimed to examine whether or not sexual minority youth constitute an at-risk group for nonsuicidal self-injury, suicidal ideation or suicide attempts during their emerging adult years. Methods: Using data from the Challenging Times Study, a population-based study of psychopathology and suicide in Ireland, analyses were conducted to test the associations between sexual minority status and the odds of any lifetime experience of nonsuicidal self-injury, suicidal thoughts or suicide attempts among Irish youth aged 19-24 years. Results: Sexual minority youth had 6.6-fold (95% CI 1.7-24.7) increased risk of nonsuicidal self-injury, a 5.0- fold (95% CI 1.3-18.3) increased risk of suicidal ideation, a 7.7-fold (95% CI 1.8-32.0) increased risk of suicide intent and a 6.8-fold (95% CI 1.6-27.6) increased risk of a suicide attempt during their lifetime compared to their heterosexual peers. Conclusions: This study shows that emerging adulthood is a period of risk for suicide and nonsuicidal self-injurious behaviour among sexual minority youth.