Online purchase intention is one of the most important research areas in management information systems and marketing science. This study extends theory of planned behavior (TPB) by including six important antecedents to online purchase intention. This study is conducted with a survey of 234 college students who have online shopping experiences. The collected survey data is used to test each hypothesis developed by using SPSS18 and AMOS18 in the research model. The results of data analysis confirm perceived ease of use (PEOU), perceived risk, and trust are essential antecedents in determining online purchase intention through behavioral attitude and perceived behavioral control.