Suicide is the third leading cause of death among young people, claiming more than 150,000 lives each year worldwide, with the majority occurring in low- and middle-income countries. Youth suicide rates are rising in many countries, including the UK, and previously declining trends have been reversed in India and China, which together account for around a third of the world's youth population. Interpreting these trends is difficult because suicide data can be affected by various biases and methodological limitations. Ecological studies that examine exposures and outcomes at the group or population level are important for assessing population factors driving suicidal trends. The global pattern of rising youth suicide rates requires explanation. Research on suicide has typically prioritized mental illness as a key determinant of global prevention, which has profound implications for understanding suicide.