Thomas Regelski, a praxial music educator, argued that only action research was the research method that showed praxis in music education. This study examined Regelski’s viewpoints on action research from critical theory and critical pedagogy. For this purpose, this study first examined what action research is, and then investigated his argument through four standpoints: the denial of positivism, the negation of generalization and universalization, the unity of theory and practice, and the emphasis on rational communication. These standpoints provide the epistemic bases for the researchers who take the positions of the praxial philosophy of music education and the action research method.