This study investigated the function of social supports and computer self-efficacy in predicting high school students' perceived effect of computer use. The study was survey method to collect data. The questionnaires were distributed to the high school students in Taiwan. 620 questionnaires were distributed and 525 questionnaires were gathered back with 84.67% return rate. The results of structural equation modeling (SEM) and model invariance analysis indicate that perceived peer support played an important role in predicting the effects of advanced computer self-efficacy. However, general computer self-efficacy was the factor more strongly associated with student computer use. The results were analyzed to provide useful insight into the development of student computer competency. The modified scale was a valid and reliable instrument for large scale population. This study provided representative results for further related studies. Educational implications and suggestions for future research are proposed. (Contains 6 tables and 2 figures.)