Public transportation helps to reduce air pollution that creates negative impacts on work performance, work quality, and productivity. The study investigates the effects of moral norms, social norms, and pro-environmental attitudes on the travel behavior of public transport commuters. A survey was carried in Greater Kuala Lumpur, and a total of 904 usable questionnaires were analyzed using Partial Least Squares. The findings showed that a pro-environmental attitude had a weak relationship to travel behavior, but moral norms played a strong instrumental influence when commuters chose public transport. Recommendation and suggestions provided.