Horse flies (Diptera: Tabanidae) are ecologically important pollinators and vectors of many disease-causing organisms, as adult females are known to mechanically transfer multiple disease agents during feeding affecting humans, livestock, and many native mammals. Scaptia (Pseudoscione) Lutz in Lutz, Araujo, & Fonseca 1918 has the widest distribution of all genera in the tribe Scionini, occurring in Australia, New Guinea, New Zealand, and South America. Seven new species of Australian S. (Pseudoscione) are described and included in an updated key to the subgenus. The new species are: S. (Pseudoscione) baylessi sp. nov. Lessard, S. (Pseudoscione) casseli sp. nov. Lessard, S. (Pseudoscione) mackerrasi sp. nov. Lessard, S. (Pseudoscione) moritae sp. nov. Lessard, S. (Pseudoscione) turcatelae sp. nov. Lessard, S. (Pseudoscione) turneri sp. nov. Lessard, and S. (Pseudoscione) wiegmanni sp. nov. Lessard. In addition, S. (Pseudoscione) occidentalis Mackerras, 1960, previously described as a subspecies, has been raised to species level. One new species significantly extends the known distribution of Scaptia into central Australia, >1,200 km NW from the nearest recorded species within the subgenus.