The Little Weir River, an anabranch of the Barwon River within the Murray–Darling basin, is located in the South Downs district of Queensland and the Orana district of New South Wales, Australia. The river leaves Barwon River, north of Mungindi, Queensland, and flows generally south-west, before reaching its confluence with the Barwon River, near Moyan, in New South Wales; descending 16 m over its 78 km course.