We tested a model of antecedents and outcomes of commitment to the environment, defined as psychological attachment and long‐term orientation to the natural world, hypothesizing that satisfaction with, investments in, and subjective norms about the environment would predict commitment, which, in turn, would predict willingness to sacrifice for the environment. In two studies, the model was supported in undergraduate and community samples, and for general commitment to the environment as well as commitment to specific proenvironmental behaviors. Individuals who are satisfied with and invested in the natural world, and who believe that those close to them value it as well, are likely to be committed to the environment and be willing to forego selfish interests to behave proenvironmentally.