ABSTRACT: BACKGROUND:Suicide is a leading cause of death among adolescents and more knowledge from high risk groups is needed in order to develop effective preventive strategies. The aim of this study was to evaluate the association between sexual minority status and suicidality in a multinational sample of European school pupils. METHODS:A self-report questionnaire was delivered to 2046 adolescents (mean age 15.34±1.01; 56.3% females) recruited from 27 randomly selected schools in 6 European countries. Suicidal ideation, measured with the Paykel Suicide Scale (PSS), and lifetime suicide attempts were compared between heterosexual and sexual minority (i.e. those with a non-heterosexual orientation) youth. Poisson regression analyses studied the longitudinal association between sexual minority status and the rate of serious suicidal ideation, measured at three time-points during a 4-month period. Several variables, including alcohol and illegal drugs use, bullying, family interaction, school-related stress, economic status, and religiosity, were included in multivariable analysis. Sex-stratified analyses evaluated the association respectively among females and males. RESULTS:Of 1958 pupils included in analysis (mean age 15.35±1.00; females 56.8%), 214 (10.9%) were categorized as sexual minority youth (SMY). When compared to heterosexual youth (HSY), SMY were significantly more exposed to substance abuse, bullying, school-related stress, and lower economic status. SMY pupils had significantly higher suicidal ideation scores (p<0.001; r 0.145) as well as higher prevalence of serious suicidal ideation (odds ratio [OR] 2.64, 95% confidence interval [CI] 1.83-3.79) and previous suicide attempts (OR 2.72, 95%CI 1.77-4.18), compared to their HSY peers. The rate of serious suicidal ideation reports during the study was significantly higher among SMY compared to HSY (rate ratio [RR] 2.55, 95%CI 1.90-3.43). A significant difference was found even when controlling for the pupils' country as well as after adjustment for alcohol and illegal drugs use, bullying, family interaction, school-related stress, economic status, and religiosity (adjusted RR 1.73, 95%CI 1.23-2.48). Stratified analyses showed significant associations between SMY status and persistent serious suicidal ideation for both sexes, with a notably strong association among male pupils (females aRR 1.51, 95%CI 1.01-2.24; males aRR 3.84, 95%CI 1.94-7.59). CONCLUSIONS:European sexual minority youth are a high-risk group for suicidality, independently from objective factors such as victimization or substance abuse. There is a need to develop primary and secondary preventive measures for sexual minority youth, including the management of context vulnerabilities and related distal stressors, before the establishment of proximal stressors. Context-targeting interventions may effectively focus on social and economic factors, as well as on the potentially different risk profile of female and male sexual minority youth.