This paper offers a systematic review of the literature on organizational categories and categorization published in the last 14 years (1999–2012). After identifying a core of roughly 100 papers on categories that appeared in management, organization, and sociology journals, we classified them based on several key dimensions, and analysed a few trends within the categorization literature. Our most surprising finding may be the fact that until recently, there was no mutual recognition of the existence of a distinct ‘literature on categories’ despite the wealth of published material on the topic. After summarizing some core theoretical features of that emergent literature, we propose integrative definitions of its core constructs and suggest several areas of research that could further enrich it in the future.