Values-engagement in evaluation involves both describing stakeholder values and prescribing certain values. Describing stakeholder values is common practice in responsive evaluation traditions. Prescribing or advocating particular values is only "explicitly" part of democratic, culturally responsive, critical, and other openly ideological traditions in evaluation, but we argue that it is "implicit" in all evaluation approaches and practices. In this article, we discuss various conceptualizations of values-engagement in evaluation. We further present a specific form of values-engaged evaluation that is committed to descriptive and prescriptive valuing, with an emphasis on its prescriptive advancement of the values of inclusion and equity. Examples from field experience illustrate these two countenances and underscore the multiple challenges invoked by intentional engagement with the values dimensions of evaluation. The examples come from evaluations of science, technology, engineering, and mathematics (STEM) educational programs. (Contains 1 table and 4 notes.)