Fully explaining organizational phenomena requires exploring not only “how” a phenomenon works – i.e., the details of its internal structure and mechanisms – but also “why” the phenomenon is present in the first place – i.e., explaining its origins and the ultimate reasons for its existence. The latter is particularly important for central questions in organizational research such as the nature of organizations, the evolution of organizational culture, or the origin of organizational capabilities. In this article, we propose that cultural evolution theory (CET) can be usefully applied to organizational scholarship to pursue such “origin” questions. CET has adapted ideas and methods from evolutionary biology to successfully explain the evolution of culture in human societies, exploring the origins of various social phenomena such as religion, technological progress, large-scale cooperation, and cross-cultural psychological variation. We elaborate how CET can be also applied to understand the evolution and origin of important organizational phenomena. We discuss how CET provides ultimate explanations using micro-evolutionary formal models and deploying macro-evolutionary tools for empirical analysis. We provide a detailed application of these ideas to explain the origin of productive organizations (e.g., firms, partnerships, guilds). We also propose several avenues for future research; in particular, we explore how CET can serve as an overarching theoretical framework that helps integrate the myriad of theories that explain how organizations operate and evolve.