Tribulus occidentalis, common name perennial caltrop,[1] is a species of flowering plant in the family Zygophyllaceae, which is native to Australia, and found in Western Australia,[1] Queensland,[2] South Australia[3] and the Northern Territory.

[4] (However, Robyn Barker asserts that it is confined to the west coast of Western Australia.

)[5] It is a prostrate perennial herb, covered in long shaggy haris and growing from 2 cm to 10 cm high.

It grows on sandy soils and its yellow flowers can be seen from February to November.

[1] It was first described in 1849 by Robert Brown, from a specimen collected on the "west coast of Australia, or on some of its islands, in the Voyage of the Beagle.