This study evaluates the effects of greenhouse gas pricing on the behavior of traveler mode choice. Based on a survey of stated travel preference, a multinomial mixed logit model was used to examine how travelers perceive the price of greenhouse gas and travel cost, and how travelers with different attributes react to them. Heterogeneous perceptions of travelers were observed: travelers were more sensitive to greenhouse gas price than travel cost. The analysis also showed significant distinctions between different traveler groups. Implications for greenhouse gas pricing and potential topics for future research are also discussed.