Physical inactivity among youth and adolescent populations is a prevailing problem in Taiwan. Seventy-one percent of 4,000 Taiwanese elementary students surveyed spend their daily leisure time watching television and 15% report spending their time playing video games. Lack of physical activity facilities is a high ranking obstruction among all perceived barriers to participation in physical activity. The purpose of this study was to investigate the associations between selected environmental and social variables including socioeconomic status (SES) and participation in physical activity among Taiwanese (n=798) high school students. Significant relationships between physical activity and physical environmental variables were found. The quantity and quality of neighborhood facilities were found to have the highest relationships (beta=.333) with high school student participation in physical activity. The home environment was found to have a significant relationship (.174) with participation in physical activity. The school environment however, was not associated (.045) with participation in physical activity. The social environment was related (p<.05) to participation in physical activity. Support from friends, parents, teachers, and the media were related to higher levels of physical activity. Neighborhood modeling (t=1.950) was found to be slightly below the critical value (t=1.960) indicating the presence of a relationship between physical activity and neighborhood modeling, but was not significant at the (p>.05) level. Regression analyses revealed a significant negative relationship (r=-.292, p<.05) between physical activity and selected environmental barriers. Family incomes of the students surveyed were found to be normally distributed. Students with families in income scale 4 (between NT$ 60,000 to 80,000) had the highest physical activity levels (211.42 minutes), while students from families in scale 1 (under NT$ 20,000) had lower levels of physical activity (150.64) minutes. Analysis of variance (ANOVA) revealed differences in physical activity levels between the different income levels (p<.05).It would appear that the physical environment was a factor in the activity levels of high school students in Taiwan. The quality and quantity of neighborhood and home facilities, along with family income are related to levels of leisure time physical activity. By integrating support from friends, parents, teachers, and the media into the models developed for intervening in physical activity through the neighborhood, homes and schools, it is possible that meaningful changes in low levels of physical activity might occur.