Reducing motorized transport has a number of positive effects on the environment and the quality of human life. Studies that provide better understanding of factors relevant to the choice of transport modes can help in creating campaigns to encourage use of environmentally friendly transport. The main goal of this study was to test the usefulness of the Theory of planned behavior (TPB), with the addition of personal norm, in predicting the intention of commuting by bicycle to university among students in Zagreb, Croatia. The data were obtained from 712 students at the University of Zagreb using an on-line survey. The results show that students mostly used public transport to go to university and that cycling is the second most common choice. The frequency of bicycle use differed due to the distance between the university and participant's home. Bicycle use first increased with the distance and then dropped at the category from 2 to 5km when it started to decrease and was the least frequent at distances longer than 10 km. All TPB components were significant predictors and explained 55% of the variance in intention of commuting by bicycle. Adding personal norm to the components of TPB made a small but significant contribution in explaining variance of the intention (additional 2%) at the same time personal norm was the weakest predictor. Practical and theoretical implications of the results are discussed.