The largest ecoregion of the Arabian Peninsula, the Arabian Desert stretches from Yemen to the Persian Gulf and Oman to Jordan and Iraq. The western edge of the desert is separated by cliffs that rise steeply from the Nile Valley. It occupies an area of 900,000 square miles and contains the Rub'al-Khali, one of the largest continuous bodies of sand in the world.

The Arabian Desert is hyper arid with average rainfall of about 1.38 inches per annum. Temperatures range from 104° to 122° Fahrenheit in the summer, to an average temperature of 41° to 59° Fahrenheit in the winter. It is part of the Deserts and Xeric Shrublands biome and the Palearctic ecozone.

The Rub’ al-Khali or "Empty Quarter", is a sedimentary basin encompassing most of the southern third of the Arabian Peninsula, including southern Saudi Arabia, and areas of Oman, the United Arab Emirates and Yemen. At 250,000 square miles the Rub' al-Khali covers more than the combined land areas of the Netherlands, Belgium and France.