Abstract
BACKGROUND: Adolescence is a critical developmental stage in the life course, and loneliness during this period has been linked to various mental health issues, social challenges, and academic difficulties. Hence, the study aimed to identify gender- and spatial variations in loneliness and its correlates among in-school adolescents in three South Asian countries. METHODS: We analyzed data from 7,903 adolescents using the latest Global School-based Student Health Survey (GSHS) datasets from Afghanistan, Bangladesh, and Pakistan. Multiple logistic regression models, adjusted for socio-demographic variables, were conducted using STATA 14. RESULTS: The prevalence of loneliness among male respondents was 12.28% [95% CI: 11.3–13.3], and 18.1% [95% CI: 16.8–19.5] in females. The prevalence of loneliness was highest among Afghan adolescents (34.8%), followed by Pakistani (11.4%) and Bangladeshi adolescents (8.4%). For both genders (male and female), loneliness was higher among the adolescents who were school truants, bullied, involved in physical fights, and experienced physical attacks. In addition, both male and female adolescents with anxiety-induced sleep disturbance, current tobacco users, and suicidal ideation had significantly higher odds of loneliness than their counterparts. Moreover, several poor mental health conditions, such as anxiety-induced sleep disturbance, bullying, suicidal ideation, and suicide plan, were significantly associated with higher odds of loneliness among in-school adolescents in Afghanistan, Bangladesh, and Pakistan. Additionally, respondents who were involved in physical fights were more likely to report feeling lonely. CONCLUSION: We identified gender and spatial variations in adolescent loneliness across three South Asian countries, highlighting the need for gender-sensitive and region-specific interventions. Policies should prioritize promoting inclusive environments and addressing cultural and resource-based challenges. To design targeted interventions, further research is needed to explore the socio-economic, environmental, and behavioral factors that influence loneliness. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12889-025-26069-7.