For reliable information on the environment, students and teachers can turn to the Encyclopedia of Earth (EoE). Based at Boston University (BU) and operated in partnership with the National Council for Science and the Environment (NCSE), the EoE is a free, fully searchable collection of articles written by scholars, professionals, educators, and experts. However—unlike Wikipedia—all EoE articles are written by recognized field experts and are reviewed and approved by qualified topic editors. This article describes how the EoE can be useful to teachers and their students in a variety of ways.