Too little is known about suicidal thoughts and behaviors at a population level to recommend appropriate preventive strategies. Using data from the Australian National Survey of Mental Health and Wellbeing (NSMHWB), this study examined rates of, and risk factors for, suicidal ideation and suicide attempts. For 10,641 respondents, the 12-month and lifetime cumulative incidence rates of suicidal ideation were 3.4% and 16.0%, respectively; the 12-month and lifetime cumulative incidence rates of suicide attempts were 0.4% and 3.6%, respectively. 12-month ideation was associated with anxiety disorders (relative risk ratio [RRR] = 3.51; population attributable risk percent [PAR%] = 19.6%), affective disorders (RRR = 11.94; PAR% = 38.8%) and substance abuse disorders (RRR = 1.85; PAR% = 6.1%). Attempts in the past 12 months were also associated with anxiety disorders (RRR = 7.06; PAR% = 37.0%), affective disorders (RRR = 12.24; PAR% = 39.5%), and substance abuse disorders (RRR = 2.09; PAR% = 7.7%). Age, marital status, and disability were associated with ideation; marital status and employment status with attempts. Approximately 12% of ideators in the sample progressed to making an attempt; employment status was the only significant predictor. Reducing suicidal ideation and attempts requires a multi-faceted approach that targets those with mental illness but also adopts population-based strategies that address other factors, such as unemployment.