Background: Adolescent cigarette smoking remains a concern globally, including in Thailand. This research aimed to elucidate the prevalence and determinants of cigarette smoking among Thai adolescents. Study Design: A cross-sectional study. Methods: A cross-sectional analysis of data from the 2021 Thailand Global School-Based Health Survey with 5545 adolescents aged 13–17 with complete information was conducted on their cigarette smoking status. Bivariate analysis and multivariable logistic regression were performed to discern the determinants of tobacco smoking among adolescents. Results: The overall weighted prevalence of cigarette smoking was 11.5% (95% confidence interval [CI]=9.7%, 13.5%), with adolescent males at 18.2% (95% CI=15.3%, 21.4%) and adolescent females at 5.6% (95% CI=4.2%, 7.4%). The multivariable logistic regression also revealed that males were more likely to be smokers (Adjusted Odd Ratio [AOR]=1.58; 95% CI=1.02, 2.45, P=0.040) compared to females. The presence of smokers in their vicinity significantly increased the odds of smoking (AOR=2.21, 95% CI=1.46, 3.36, P<0.001). Current alcohol use (AOR=3.37, 95% CI=2.21–5.14, P<0.001) and current marijuana use (AOR=4.53, 95% CI=2.06, 9.99, P<0.001) were both significant determinants of smoking. Notably, early initiation of cigarette use (before age 14) was associated with a lower likelihood of current smoking (AOR=0.54, 95% CI=0.33, 0.92, P=0.022). Conclusion: With an overall prevalence of smoking among adolescents at 11.5%, our study highlights a significant public health concern. The positive determinants of the identified tobacco smoking include being male, having smokers in their vicinity, and currently using alcohol, and marijuana, while early initiation of cigarette use before age 14 is identified as an inverse determinant.