This conceptual paper presents the analytical theory of agency (ATA), an overlooked philosophical approach to the concept of action, to develop its theoretical basis in routines research in which the constructs of action and agency play crucial roles. It expounds, in the framework of ATA, the ideas of the spectrum of intentionality, kinds of action, and collective agency, which help advance the rigor of action-theoretical concepts in routines research as well as reveal the rationale of the microfoundational approach to routine actions. To uncover the developmental potential of ATA, the article discusses the most crucial conceptual challenges for routines research; it also briefly examines the limitations and future work related to using ATA in the management field.