The Canadian Prairies (usually referred to as simply the Prairies in Canada) is a region in Western Canada. It includes the Canadian portion of the Great Plains and the Prairie provinces, namely Alberta, Saskatchewan, and Manitoba. These provinces are partially covered by grasslands, plains, and lowlands, mostly in the southern regions. The northernmost reaches of the Canadian Prairies are less dense in population, marked by forests and more variable topography. If the region is defined to include areas only covered by prairie land, the corresponding region is known as the Interior Plains. Physical or ecological aspects of the Canadian Prairies extend to northeastern British Columbia, but that area is not included in the political use of the term.

The prairies in Canada are a biome of temperate grassland and shrubland within the prairie ecoregion of Canada. This ecoregion consists of northern mixed grasslands in Alberta, Saskatchewan, and southern Manitoba, as well as northern short grasslands in southeastern Alberta and southwestern Saskatchewan. The Prairies Ecozone of Canada includes the northern tall grasslands in southern Manitoba and Aspen parkland, which covers central Alberta, central Saskatchewan, and southern Manitoba. The Prairie starts from north of Edmonton and it covers the three provinces in a southward-slanting line east to the Manitoba–Minnesota border. Alberta has the most land classified as prairie, while Manitoba has the least, as the boreal forest begins more southerly in Manitoba than in Alberta.

The core climate of the Canadian prairie region is defined as a semi-arid climate and is often based upon the Köppen climate classification system. This type of classification encompasses five main climate types, with several categoric subtypes based on the precipitation pattern of the region. The majority of the prairie provinces experience snowy, fully humid continental climates with cool summers (known as Group D), and subarctic climate, also known as class Dfc on the Köppen climate scale. The southernmost regions of the prairies tend to experience fully humid continental climates with warm summers, Dfb. In parts of southwestern Saskatchewan and southern Alberta in Palliser's Triangle, the climate is drier with greater evapotranspiration, resulting in BSk, cold semi-arid climates.

Precipitation events in the Canadian prairies are very important to study as these locations make up 80% of the country's agricultural production. On average, 454 mm (18 in) of precipitation falls on the prairies each year. Out of the three prairie provinces, Saskatchewan obtains the least amount of precipitation annually (395 mm [16 in]), with Manitoba receiving the most at 486 mm (19 in). Most rainfall typically happens in the summer months such as June and July. With the high humidity of the prairies, tornadoes are likely to occur—marking central Saskatchewan, Alberta and southern Manitoba as high probability areas. Approximately 72% of tornadoes in Canada are seen across the prairies due to the capability of summer thunderstorm precipitation to mechanically mix with the air adjacent to the relatively flat surface of the region.

Although the Prairie Provinces region is named for the prairies located within Alberta, Saskatchewan and Manitoba, the physical geography of the three provinces is quite diverse, consisting of portions of the Canadian Shield, the Western Cordillera and the Canadian Interior Plains. The plains comprise both prairies and boreal plains forests while, with the exception of freshwater along the Hudson Bay, the shield is predominantly forested.

Three main grassland types occur in the Canadian prairies: tallgrass prairie, mixed grass prairie, and fescue prairie (or using the WWF terminology, northern tall grasslands, northern mixed grasslands, and northern short grasslands). Each has a unique geographic distribution and characteristic mix of plant species. All but a fraction of 1% of the tallgrass prairie has been converted to cropland. What remains occurs on the 6,000 km² (2,300 sq mi) plain centred in the Red River Valley in Manitoba. Mixed prairie is more common and is part of the dry interior plains that extend from Canada south to the U.S. state of Texas.

More than half of the remaining native grassland in the Canadian prairies is mixed. Though widespread in southern Saskatchewan and southeastern Alberta, because of extensive cattle grazing, it is estimated that only 24% of the original mixed prairie grassland remains. Fescue prairie occurs in the moister regions, occupying the northern extent of the prairies in central and southwestern Alberta and west-central Saskatchewan.

The southwestern Canadian prairies, supporting brown and black soil types, are semi-arid and highly prone to frequent and severe droughts.