Traditional masculinity is hypothesized to be associated with suicidal ideation, and traditional masculinity is predicted to interact with stressors, intensifying suicidal ideation. Cross-sectional and prospective data from a study of 2,431 young adults was analyzed using hierarchical regression main effects and interaction models. Traditional masculinity was associated with suicidal ideation, second only in strength to depression, including when controlling for other risk factors. Prospective effects were substantially weaker. There was mixed evidence for traditional masculinity by stress interactions. The results provide preliminary support for the role of traditional masculinity in suicidal ideation, but the relationship should be tested in studies of suicide attempts and mortality. Implications for prevention and intervention are explored.