AbstractBackgroundUnderstanding the burden and determinants of suicide during adolescence is key to achieving global health goals. We examined the prevalence and determinants of self-reported suicidal ideation and attempts among younger (13–15 years) and older adolescents (16–17 years).MethodsPooled prevalence estimates with 95% confidence interval, were calculated for suicide ideation and attempts for 118 surveys from 90 countries that administered the Global School-based Student Health Survey (GSHS) to adolescents (13–17 years of age) from 2003 to 2017. Indicators (including individual and social factors) associated with suicidal ideation and attempts were determined from multivariable linear regressions on key outcomes.ResultsThe prevalence of suicidal ideation representing 397,299 adolescents (51.3% female) was significantly higher among girls than boys whereas attempts did not differ by age or sex. Being bullied, or having no close friends was associated with suicidal ideation among girls 13–15 years and 16–17 years, respectively. Among all boys, being in a fight and having no close friends was associated with suicidal ideation with the addition of serious injury for boys 13–15 years. Common to all younger adolescents was an association of suicide attempt with being bullied and having had a serious injury. Among young boys, having no close friends was an additional indicator for suicide attempt. Having no close friends was associated with suicide attempt in older adolescents with the addition to being bullied in older girls and serious injury in older boys.ConclusionsBuilding positive social relationships with peers and avoiding serious injury appear key to suicide prevention strategies for vulnerable adolescents. Targeted programs by age group and sex for such indicators could improve mental health during adolescence in low and middle-income countries, given the diverse risk profiles for suicidal ideation and attempts.