This article presents a comprehensive taxonomy of essential competencies for program evaluators. First, the authors provide a rationale for developing evaluator competencies, along with a brief history of the initial development and validation of the taxonomy of essential evaluator competencies in King, Stevahn, Ghere, and Minnema (2001). Second, they present a revised version of that taxonomy and describe the revision process. Third, a crosswalk accompanying the taxonomy indicates which competencies address standards, principles, and skills endorsed by major evaluation associations in North America. Finally, the authors identify future needs related to the taxonomy, including the need for validation research, a shared understanding of terms, and the construction of descriptive rubrics for assessing competence.