The roles of systematics in the field of conservation biology are well understood and accepted for many organisms. However, the role of systematics and taxonomy has not been reviewed in the context of species protection and management of freshwater gastropods. We provide a thorough review of the relevant theoretical literature in systematics and taxonomy and illustrate with recent examples of species delineation and taxonomy in North American freshwater gastropods that these fields play key roles in the practical designation of conservation management units. We summarize some aspects of the biology of freshwater gastropods that can confound taxonomic and management efforts. Based on our review, we recommend that effective conservation plans include the systematic research necessary to recognize unique organismal lineages as primary conservation management units. This strategy must be combined with consistent and rigorous nomenclature, taxonomy, and dissemination of research findings so that all parties have access to the highest quality information.