AimsTo examine the contributions of psychosocial factors (attitude towards drinking, perceived drinking norms [PDNs], perceived behavioural control [PBC]), and biological sex on drinking intention and behaviours among rural Thai adolescents.DesignA cross‐sectional study design.MethodsIn 2022, stratified by sex and grade, we randomly selected 474 rural Thai adolescents (Mage = 14.5 years; SD = 0.92; 50.6% male) from eight public district schools in Chiang Mai Province, Thailand, to complete a self‐administered questionnaire. Structural equation modelling with the weighted least square mean and variance adjusted was used for data analysis.ResultsAll adolescents' psychosocial factors contributed significantly to the prediction of drinking intention, which subsequently influenced their drinking onset, current drinking and binge drinking pattern in the past 30 days. PDNs emerged as the strongest psychosocial predictor of drinking intention, followed by PBC. Rural adolescents' drinking intention significantly mediated the relationship between all psychosocial factors and drinking behaviours either fully or partially. The path coefficient between drinking attitude and drinking intention was significantly different between males and females.ConclusionDifferent from previous studies focus on adolescents' drinking attitude, rural Thai adolescents' PDNs play a significant role on their drinking intention and subsequently their drinking onset and patterns. This nuanced understanding supports a paradigm shift to target adolescents' perceived drinking norms as a means to delay their drinking onset and problematic drinking behaviours.ImpactHigher levels of perceived drinking norms significantly led to the increase in drinking intention among adolescents. Minimizing adolescents' perceptions of favourable drinking norms and promoting their capacity to resist drinking, especially due to peer pressure, are recommended for nursing roles as essential components of health education campaigns and future efforts to prevent underage drinking.Patient or Public ContributionIn this study, there was no public or patient involvement.