The prevalence of betel nut chewing among junior high school students is highest in the eastern region of Taiwan (Lin, 1990). Although there is some research on the prevalence rate, little effort has been paid to developing a classification of betel nut chewing behavior applicable to adolescents. Eight-hundred and forty-three students, including 435 males (51.6%) and 408 females (48.4%), 552 non-aborigines (65.5%) and 291 aborigines (34.5%), completed a questionnaire concerning betel nut chewing behavior, beliefs (perceptions) toward betel nut chewing, self-esteem, and locus of control. Using a cluster analysis, this study identified 3 sub-types of betel nut chewing behaviors. They were identified as "Self-regulation oriented" (Internally controlled-oriented), "Indigenously oriented" (Taiwan culture-oriented), and "Symbolically oriented" (Externally controlled-oriented). The validity of clusters was explored in terms of gender and ethnicity. This study describes the implications for reducing betel nut chewing behaviors among adolescents. (Contains 3 figures and 7 tables.)