In this paper we address the pervasive tendency in community psychology to treat values like social justice only as general objectives rather than contested theoretical concepts possessing identifiable empirical content. First we discuss how distinctive concepts of social justice have figured in three major intellectual traditions within community psychology: (1) the prevention and health promotion tradition, (2) the empowerment tradition, and most recently, (3) the critical tradition. We point out the epistemological gains and limitations of these respective concepts and argue for greater sensitivity to the context dependency of normative concepts like social justice. More specifically, we point to a pressing need in community psychology for an epistemology that: (1) subsumes both descriptive and evaluative concepts, and (2) acknowledges its own embeddedness in history and culture without thereby reducing all knowledge claims to the status of ideology. Finally, we describe and demonstrate the promise of what we are calling a social ecological epistemology for fulfilling this need.