Plasmids are ubiquitous in the bacterial world. In many microorganisms, plasmids have been implicated in important aspects of bacterial physiology and contribute to horizontal gene transfer. In contrast, knowledge on plasmids of the enteropathogen Clostridioides difficile is limited, and there appears to be no phenotypic consequence to carriage of many of the identified plasmids. Emerging evidence suggests, however, that plasmids are common in C. difficile and may encode functions relevant to pathogenesis, such as antimicrobial resistance and toxin production. Here, we review our current knowledge about the abundance, functions and clinical relevance of plasmids in C. difficile.