BackgroundDespite the negative impact of chronic school absenteeism on the psychological and physical health of adolescents, data on the burden of adolescent chronic school absenteeism (ACSA) and interventions and programs to address it are lacking. We estimated the global, regional and national level prevalence of ACSA and its correlation with violence and unintentional injury, psychosocial, protective, lifestyle, and food security-related factors among in-school adolescents across low and middle-income, and high-income countries (LMICs–HICs).ObjectivesThis study aimed to estimate the prevalence of chronic school absenteeism (CSA) as well as to determine its associated factors among in-school adolescents across 71 low-middle and high-income countries.MethodsWe used data from the most recent Global School-based Student Health Survey of 207,107 in-school adolescents aged 11–17 years in 71 LMICs-HICs countries across six WHO regions. We estimated the weighted prevalence of ACSA from national, regional and global perspectives. Multiple binary logistic regression analyses were used to estimate the adjusted effect of independent factors on ACSA.ResultsThe overall population-weighted prevalence of CSA was 11·43% (95% confidence interval, CI: 11·29–11·57). Higher likelihood of CSA was associated with severe food insecurity, peer victimisation, loneliness, high level of anxiety, physically attack, physical fighting, serious injury, poor peer support, not having close friends, lack of parental support, being obese, and high levels of sedentary behaviours. Lower likelihood of CSA was associated with being female (odds ratio, OR = 0·76, 95% CI: 0·74–0·78).ConclusionOur findings indicate that a combination of different socio-economic factors, peer conflict and injury factors, factors exacerbate CSA among adolescents. Interventions should be designed to focus on these risk factors and should consider the diverse cultural and socioeconomic contexts.