Suicide is a leading cause of death worldwide; however, the prevalence and risk factors for the immediate precursors to suicide - suicidal ideation, plans and attempts - are not wellknown, especially in low- and middle-income countries. To report on the prevalence and risk factors for suicidal behaviours across 17 countries. A total of 84 850 adults were interviewed regarding suicidal behaviours and socio-demographic and psychiatric risk factors. The cross-national lifetime prevalence of suicidal ideation, plans, and attempts is 9.2% (s.e.=0.1), 3.1% (s.e.=0.1), and 2.7% (s.e.=0.1). Across all countries, 60% of transitions from ideation to plan and attempt occur within the first year after ideation onset. Consistent cross-national risk factors included being female, younger, less educated, unmarried and having a mental disorder. Interestingly, the strongest diagnostic risk factors were mood disorders in high-income countries but impulse control disorders in low- and middle-income countries. There is cross-national variability in the prevalence of suicidal behaviours, but strong consistency in the characteristics and risk factors for these behaviours. These findings have significant implications for the prediction and prevention of suicidal behaviours.