Riccia L. is the largest and most diverse genus within the complex thalloid liverworts, with over 200 species worldwide. Along with the aquatic genus Ricciocarpos Corda, it is one of two genera in the family Ricciaceae. The Ricciaceae are unique in having the capsule borne within the plants tissue. Riccia species are further recognised by their strap-shaped thallus that may be unbranched but is typically bifurcating in a Y-pattern. The genus is most diverse in Mediterranean-type environments, particularly in southern Africa. This paper documents all known Riccia taxa occurring in the northern part of the Northern Territory, north of 18°S.