The Marree Man, or Stuart's Giant, is a modern geoglyph discovered by air on 26 June 1998. It appears to depict an indigenous Australian man hunting birds or wallabies with a boomerang. It lies on a plateau at Finnis Springs 60 km west of the township of Marree in central South Australia. It is just outside the 127,000 square kilometres Woomera Prohibited Area. The figure is 4.2 km tall with a perimeter of 15 by 28 kilometres. Although it is the second largest geoglyph in the world, its origin remains a mystery, with not a single witness to any part of the expansive operation. The name "Stuart's Giant" was given to it in a fax sent to the media anonymously by those believed to have created the figure, after John McDouall Stuart.

Shortly after its discovery, the site was closed by the South Australian government following legal action taken in late July by Native Title Claimants but, as of 2010, joy flights were still allowed over the site as Native title falls under federal government jurisdiction.

The Marree Man geoglyph depicts a man holding either a throwing stick once used to disperse small flocks of birds, or a boomerang.

The lines of the figure were 20–30 cm deep at the time of discovery and up to 35 metres wide. The image is gradually eroding through natural processes, but because the climate is extremely dry and barren in the region, the image is still visible as of 2013. While there is a layer of white chalk material slightly below the red soil, the figure was not defined to this depth.

Trevor Wright, a charter pilot flying between Marree and Coober Pedy in the remote north of South Australia spotted the figure from the air on 26 June 1998. The discovery of the geoglyph fascinated Australians due to its size and the mystery surrounding how it came to be there. At the time of the discovery there was only one track entering and one track exiting the site and no footprints or tyre marks were discernible.

Shane Anderson from the William Creek Hotel, located 200 km (124 mi) north-west of the town of Marree claimed the hotel received an anonymous fax describing the location of the artwork, but they ignored it, dismissing the fax as a joke.

When the site was discovered, several items were found in a small pit what appeared to be a satellite photo of the figure, a jar containing a small flag of the US, and a note which referred to the Branch Davidians, a religious group infamous for being attacked in the Waco raid in 1993. These were the only man-made items found at the site when it was discovered.