Paragonimus is a genus of flukes (trematodes) and is the only genus in the monotypic family Paragonimidae. Some tens of species have been described, but they are difficult to distinguish, so it is not clear how many of the named species may be synonyms. The name Paragonimus is derived from the combination of two Greek words, “para” (on the side of) and “gonimos” (gonads or genitalia). Several of the species are known as lung flukes. In humans some of the species occur as zoonoses; the term for the condition is paragonimiasis. The first intermediate hosts of Paragonimus include at least 54 species of freshwater snails from superfamilies Cerithioidea and Rissooidea.

The most prominent species of Paragonimus in human medicine is Paragonimus westermani, an infectious lung fluke originating in eastern Asia. Worldwide, about nine species of Paragonimus are known to cause human paragonimiasis in which many of the species reside in East Asia, West Africa, and in North and South America.