Although most people are aware of the harmful CO ₂ emissions produced by the transport sector threatening life on earth now and in the future, they do not eco-drive. Eco-driving improves the vehicle's fuel or energy economy and reduces greenhouse gas emissions. We investigated the motivational predictors of eco-driving based on the theory of self-concordance (i.e., the consistency between a behavior/goal with the person's pre-existing values and interests). Data from a cross-sectional online survey with 536 German drivers revealed that self-reported eco-driving was significantly predicted by sustained effort towards eco-driving, which in turn was predicted by self-concordance variables. Therefore, individuals pursuing eco-driving out of strong interest or deep personal beliefs (i.e., autonomous motivation) as opposed to external forces or internal pressures (i.e., controlled motivation) reported greater effort towards this behavior. Furthermore, biospheric striving coherence, i.e., the coherence between personal valuable biopsheric values (i.e., values addressing the well-being of the environment/biosphere) and eco-driving, significantly predicted effort towards eco-driving. In sum, our results suggest that autonomous rather than controlled motives and coherence between behavior and intrinsic rather than extrinsic values are relevant predictors for eco-driving. We discuss implications for future strategies and interventions fostering eco-driving in the long term.