Power has always been an element of the program evaluation field, however, it has traditionally been attributed a negative connotation. With that in mind, power is seen as a force possessed to some extent by different stakeholders that can be imposed over others, and by which certain views, ideas, and decisions can be adopted. Given that program evaluation has a political character in which power is always present, we seek to explore a different notion of this concept. In this paper, we intend to take advantage of Michel Foucault's ideas to explore power in the program evaluation field. We illustrate the introduction of these concepts in collaborative evaluations and in doing so, we also explore power as well as power-knowledge relations, adopting a transformative perspective on power. The introduction of these concepts in collaborative evaluation is useful in illustrating how they can be used in non-collaborative evaluations.