This chapter examines the notion of parsimony. It provides an overview of what is typically considered the origin of parsimony as a theoretical virtue, as well as more recent interpretations. The chapter also identifies several formulations that apply across both ontology and ideology. Additional distinctions are introduced, including qualitative versus quantitative and fundamental versus derivative. The chapter concludes by noting the lack of a unified account of parsimony, which leaves the concept problematic within philosophical discourse and in need of a more precise characterisation.