Purpose: We describe the timing of suicidality across the life span in three cohorts of sexual minority adults. We hypothesized that suicide attempts coincide with the coming out period and that younger sexual minority people, who grew up in more accepting social environments, will have lower prevalence of suicide attempts than older generations. Methods: A U.S. national probability sample of 1518 sexual minority adults in three age cohorts of 18-25, 34-41, and 52-59 years (collected 2016-2018) completed a self-administered survey. Results: Sexual minority adults had high prevalence of lifetime suicidal thoughts, plans, and attempts, with the highest attempted suicides in the younger cohort (30.8%, 95% confidence interval [CI] = 26.8-35.1) compared with the middle (23.7%, 95% CI = 19.0-29.1) and older (20.3%, 95% CI = 16.3-25.1) cohorts. There were no differences in suicidal behavior by race and ethnicity or between men and women, but gender nonbinary people had higher prevalence of suicidal thoughts. The mean age at suicidal thoughts, plans, and attempts tracked closely with age of first realization of sexual minority identity. Most suicide attempts (60.9%) occurred within 5 years of realizing one's sexual minority identity, but a significant proportion of attempts (39.1%) occurred outside this range. Conclusion: Our findings are contrary to the hypothesis that younger cohorts of sexual minority people are at lower risk of suicidality.