As part of the Philosophy of Science series of Invited Commentaries, this article on critical theory describes the origins of this research paradigm and its key concepts and orientations (ontology, epistemology, axiology, methodology, and rigor). The authors frame critical theory as an umbrella term for different theories, including feminism, antiracism, and anticolonialism. They emphasize the structural analysis that critical scholars conduct to uncover and sometimes address the role that social, political, cultural, economic, ethnic, and gender factors play in health professions education. They note the importance of acknowledging one's social location when doing critical research and highlight the core values of democracy and egalitarianism that underpin critical research. Methodologically, the authors stress how critical scholars reject singular truths in favor of more nuanced portraits of concepts and events, mobilize inductive approaches over deductive ones, and use critical theory to develop their projects and analyze their data. Following upon this elucidation of critical theory, the authors apply this paradigm to analyze the sample case of Lee, a medical resident who was involved in a medication error. The authors conclude that research conducted in the critical tradition has the potential to transcend individualistic accounts by revealing underlying structural forces that constrain or support individual agency.