In physical geography, steppe (from Slavic step') is a plain without trees (apart from those near rivers and lakes); it is similar to a prairie, although a prairie is generally reckoned as being dominated by tall grasses, while short grasses are said to be the norm in the steppe. It may be semi-desert, or covered with grass or shrubs, or both depending on the season. The term is also used to denote the climate encountered in such regions, too dry to support a forest but not so dry as to make it a desert.

The world's largest zone of steppes are found in central Russia and neighbouring republics of Central Asia. The steppes begin east of the Volga river and extend through desert or semi-desert south of the Ural Mountains and to the north and east of the Caspian Sea. To the east of the Caspian Sea they extend through Turkmenistan, Uzbekistan and Kazakhstan to the mountain ranges of Mongolia, China, Kyrgyzstan, Tajikistan and Afghanistan. To the north on the eastern side of the Urals is the forested West Siberian Plain which extends nearly to the Arctic Ocean.