Reflexivity has in the past few decades become a core concept and concern in the social sciences and has increasingly shaped (meta) theoretical debates in the field of International Relations (IR) since the 1980s. While there is no single understanding of what reflexivity (sometimes referred to as reflectivity or self-reflexivity) means or entails, a broad consensus identifies reflexivity as the capacity to reflect on one’s own epistemic situation and process, and how these affect the nature and meaning of the knowledge one produces. As such, there are different strands of reflexive or reflexivist scholarship in IR, based on how these different elements are envisaged and addressed. Expanding beyond mere “control against bias,” which was a core concern of American behavioralist scholars in the 1950s, reflexivity has turned from a standard for the pursuit of “objective” knowledge to a problematization of, and response to, the historicity and social-situatedness of knowledge. Discussions of reflexivity in IR are thus typically generated within self-labelled post-positivist intellectual traditions, wherein reflexivity becomes a fundamental epistemological, methodological, and/or ethical problem that requires constant engagement as an integral part of the research process, and that also affects other aspects of the scholarly vocation and practice, including pedagogy and public engagement. Within this broad literature, this annotated bibliography will cover works that have contributed to clarifying and promoting reflexivity as a metatheoretical standard for IR (i.e., reflexivity as a core question for epistemology, ontology, methodology, and ethics), but also works that have contributed to an empirical understanding of IR’s historical and social embeddedness. The reason for including the latter within reflexivist IR—in the broad sense of the term—despite the fact that many authors of such works have not necessarily self-identified as reflexivists, is that they in effect provide an important empirical basis upon which the problematization and clarification of the problem of reflexivity become possible in philosophical and praxical terms. Indeed, in most social sciences such empirical investigation of the embeddedness of knowledge within social structures and orders is provided by historiographical and sociological studies on the sociohistorical conditions of the “production” or “constitution” of knowledge. But IR scholars have in the past few decades developed an in-house historiographical and “science studies” agenda that has increased the whole community’s understanding of the specific sociopolitical and institutional contexts and factors that shape its nature and evolution. The two literatures are therefore conceptually and practically connected, and together contribute to whatever level of reflexivity IR as a field can now be said to enjoy.