Objectives Most smokers begin using tobacco in their teens and recent reports indicate that smoking prevalence is climbing among youth in Taiwan. The purpose of this paper was to determine the associated factors of susceptibility of youth smoking by different types of schools. Methods A total of 4689 junior high students and 3918 senior high students participated in a school-based survey to determine the associated factors of susceptibility of youth smoking through anonymous self-administered questionnaire in 2004–2005. Results Susceptibility to initiate smoking ranged from 11.3% for junior high to 12.7% for general senior high and 12.4% for vocational senior students. For all/male smoking-susceptible students, more junior high students had one or more parents or best friends who smoked than did general or vocational senior high students. For all/female smoking-susceptible students, significantly more junior high students experienced secondhand smoke in public places than did non-susceptible students. Conclusions Developing tailored, comprehensive smoking-prevention programs for junior high students should involve establishing tobacco-free households and communities.