This article examines the challenges and the promises of complexity theory as a framework for teacher education research. One purpose is to elaborate the basic tenets of complexity theory, summarize its previous uses, and identify key challenges. A second purpose is to propose a new research platform that combines complexity theory with critical realism (CT-CR) and prompts a new set of empirical questions and research methods. This article concludes that the combination of complexity theory and critical realism offers a unique platform for teacher education research, which has theoretical consistency, methodological integrity, and practical significance.