Sixty 2nd, 5th, and 8th graders were interviewed on their moral and ecological reasoning about the 1990 Exxon Valdez oil spill that occurred in Prince William Sound, Alaska. Results showed that children understood that the oil spill negatively affected the local Alaskan shoreline, marine life, fishermen, recreationists, and the oil company. Children cared that harm occurred to the shoreline and marine life and conceived of both types of harm as violating a moral obligation. Fifth and 8th graders, compared with 2nd graders, used a greater proportion of anthropocentric reasoning (e.g., that nature ought to be protected to protect human welfare) and biocentric reasoning (e.g., that nature has intrinsic value, rights, or a teleology). Discussion focuses on how studying children's reasoning about nature not only extends the bounds of what counts as moral--to include a relationship with the natural world--but also provides a unique means by which to conduct basic research on children's moral development.