Suicide is second to only accidental death as the leading cause of mortality in young men across the world. Although suicide rates for young men have fallen in some high-income and middle-income countries since the 1990s, wider mortality measures indicate that rates remain high in specific regions, ethnic groups, and socioeconomic groups within those nations where rates have fallen, and that young men account for a substantial proportion of the economic cost of suicide. High-lethality methods of suicide are preferred by young men: hanging and firearms in high-income countries, pesticide poisoning in the Indian subcontinent, and charcoal-burning in east Asia. Risk factors for young men include psychiatric illness, substance misuse, lower socioeconomic status, rural residence, and single marital status. Population-level factors include unemployment, social deprivation, and media reporting of suicide. Few interventions to reduce suicides in young men have been assessed. Efforts to change help-seeking behaviour and to restrict access to frequently used methods hold the most promise.