Cenchrus echinatus is a species of grass known by the common names southern sandbur, spiny sandbur, southern sandspur, and in Australia, Mossman River grass. It is native to North and South America.

It is a clump-forming annual grass growing up to 80 cm (31 in) tall. The leaves occur with or without hairs and measure up to 12 mm (0.47 in) wide. The ligule is a fringe of hairs. The grass has barbed burrs of 4–10 mm (0.16–0.39 in) long.

In Australia it forms an invasive weed in coastal situations.