This research examines the time used by teenagers, aged 16 to 19 years, the types of activities teenagers do, and the impact of internet usage on their non-fixed activities during weekdays. The data employed for this research is the 2009 National Household Travel Survey (NHTS 2009). For this study, socio-demographic factors (such as age, gender, race, work status, immigrant status, number of individuals in the household, number of children in the household, number of workers in the household, household income, and others), non-fixed activities (at home, shopping, personal business, physical, recreational and social, meals, religious, and others), time spent on non-fixed activities, and internet use among teenagers were taken into consideration. The methodology in this research uses an ordered response model to analyze internet usage, and a Multiple Discrete Continuous Extreme Value model (MDCEV) to analyze the activity participation. The results show that individual and household demographic characteristics have an impact on internet usage, as well as, internet usage is found to have a significant impact on the activity participation behavior of teenagers. / text