This study introduces a causal model which links measures of computer experience, computer-related attitudes, computer-related confidence, and perceived computer-based knowledge. The model is based on the concept of computer literacy, and on an attitude-behavior theory which argues that beliefs lead to attitudes, and that attitudes are an important precursor to behavior. The causal model suggests that computer use has a positive effect on perceived computer self-confidence, as well as on computer-related attitudes. The model hypothesizes that computer attitudes and computer confidence have a positive mutual effect, and that both factors positively effect perceived computer knowledge. Questionnaires were administered to 309 students in Grades 7-12. The theoretical model was tested by structural equation analysis (LISREL) and, as expected, all causal effects, including the reciprocal one, were confirmed. The contribution and relevance of these findings to future educational research and to school practices are discussed.