AbstractAlthough collegial relationships are among the most prevalent types of interpersonal relationships in our lives, they have not been the subject of much philosophical study. In this paper, we take the first step in the process of developing an ethics of collegiality by establishing what qualifies two people as colleagues and then by determining what it is that gives value to collegial relationships. We argue that A and B are colleagues if both exhibit sameness regarding at least two of the following three features: (i) the same work content or domain of activity; (ii) the same institutional affiliation or common purpose; and/or (iii) the same status or level of responsibility. Moreover, we describe how the potential value of collegial relationships is grounded in the relationship goods that two colleagues have reason to generatequacolleagues, namely, collegial solidarity and collegial recognition. Two interesting conclusions that can be drawn from our analysis are that one has to be proficient at one’s work if one is to be considered a good colleague and that we are also more likely to be better colleagues if we regard the work we do as valuable. Finally, we draw special attention to the working conditions that are conducive to the generation of good collegial relationships and suggest some policies to promote them.