For years, Thailand’s campaign against smoking has achieved great success. The campaign has resulted in an overall reduction in smoking. Despite such success, the prevalence of children smoking, as well as youths, is on the rise. To replace adults who smoke less, these young smokers are being targeted by cigarette producers. This study, therefore, is aimed at exploring factors that influence the smoking behavior of adolescents. The study employed data from the project "Impacts of Smoking Control Policies in Thailand". Data were collected in the second round survey in 2006 which involved 968 adolescents aged 13 to 17 years. The study applied logistic regression technique to analyze factors influencing adolescent smoking behavior. This study revealed a number of factors that influence smoking behavior of adolescents. These factors included sex, age, education level, knowledge about the impact of smoking, belief about smoking, drinking experience, number of close friends who smoked, restriction on smoking areas in the home and frequency of viewing warning labels on cigarette packets. All of the above mentioned factors are statistically significant to smoking behavior of the young. The sex factor is considered to be the most powerful factor attributed to smoking. Male teenagers have a 9.6 times greater chance of smoking than female teenagers. Drinking experience is the second most influential factor. Adolescents who have drunk more than 5 times in total are 3.9 times more likely to smoke than those without drinking experience. Teenagers who drink 1-5 times have a 2.5 times higher chance of smoking than those who have never drunk any alcoholic beverage. Another finding was that teenagers from families that had restricted smoking areas in the home were 2.4 times likelier to smoke than those from families that prohibited smoking in the home. Due to the fact that adolescents spend most of their time with their families and at school, this study views that these two components are crucial to the campaign against and for the prevention of smoking in adolescents. The study also views alcoholic drinking as a stimulant to smoking. Therefore, it suggests that an anti-drinking campaign should be conducted in parallel with a non-smoking campaign.