As is the case with other fields, there is motivation for studying the impact that the body of evaluation theory literature has within and outside the field. The authors used journal articles written by theorists included on the evaluation theory tree by Alkin and Christie (2004; Christie & Alkin, 2008) and published in the Web of Science, an online academic database, as a data source to address the questions: "What fields of knowledge do evaluation theorists draw upon in their publications?" and "What fields draw upon the published articles of evaluation theorists in their work?" The bibliometric analysis of 731 journal articles published by evaluation theorists shows that evaluation is an intellectual field that is strongly informed by psychology and education, as well as a range of other subjects. There are some consistencies in the publishing patterns of the theorists across the three branches of the theory tree (methods, use, and valuing), but multidimensional scaling maps show that each branch also exhibits a distinctive character of its own. References to a random sample of 500 articles from a subset of 9 theorists indicate that these theorists were cited not only in the areas that they themselves cite, but also in areas beyond where they routinely publish. (Contains 7 tables, 5 figures, and 2 notes.)