Palliser's triangle is a region at the southern end of the Canadian Prairie Provinces, bounded roughly by the U.S. Border, the Rocky Mountains, and a line drawn between Calgary, Alberta and where the border between Saskatchewan and Manitoba meets the US/Canadian border. It can be considered an extension of what Zebulon Pike described as the "Great American Desert" into Canada.

The region was named after John Palliser who first described it during an 1863 expedition.

As one gets closer to the Rocky Mountains, a rain shadow effect makes the land drier and drier, making the farming of high-yield cash crops such as corn or grain sorghum more difficult. However, as one proceeds north, longer days during the summer provide a longer growing season, and a lower dew point due to the cold provides more rain. So, as one moves northward, the eastern edge of the dry region drifts steadily westward until it hits the Rockies west of Calgary.

Because it was ill-suited to agriculture, at least before widespread irrigation, Palliser's Triangle was considered Canada's cattle country.