To determine the association between sleep, mental disorders, and suicidal ideation (SI) and suicide attempt (SA) among adults in the community. Cross-sectional. National Comorbidity Survey (n = 8098). A representative sample of adults in the United States. Multiple logistic regression analyses were used to determine the association between usual number of hours of sleep during a 24-h period and SI and SA (past 12 months and lifetime). Analyses were adjusted for differences in demographic characteristics and comorbid mental disorders. Additional analyses examined the relationship between hours of sleep and the odds of SA among adults with SI, compared with SI without SA. Short sleep was associated with significantly increased odds of SI (OR 2.5, 95% CI: 1.6-3.9) and SA (OR 3.0, 95% CI: 1.4-6.4), and with SA among those with SI (past 12 months). These associations persisted after adjusting for differences in demographic characteristics and mental disorders, though the links between short sleep and SA among those with SI were no longer statistically significant after adjusting for panic, mood, and substance use disorders. Short sleep appears to be associated with increased likelihood of SI and SA, independent of the effects of comorbid mental disorders, among adults in the community. Among adults with SI, short sleep is associated with increased odds of SA, and this association seems largely related to the presence of panic attacks, mood, and substance use disorders. Future studies should investigate the nature of these relationships, and whether and how mental health problems may play a role.