The Tatars () is an umbrella term for different Turkic ethnic groups bearing the name "Tatar". Initially, the ethnonym Tatar possibly referred to the Tatar confederation. That confederation was eventually incorporated into the Mongol Empire when Genghis Khan unified the various steppe tribes. Historically, the term Tatars (or Tartars) was applied to anyone originating from the vast Northern and Central Asian landmass then known as Tartary, a term which was also conflated with the Mongol Empire itself. More recently, however, the term has come to refer more narrowly to related ethnic groups who refer to themselves as Tatars or who speak languages that are commonly referred to as Tatar.

The largest group amongst the Tatars by far are the Volga Tatars, native to the Volga-Ural region (Tatarstan and Bashkortostan), who for this reason are often also known as "Tatars" in Russian. They compose 53% of the population in Tatarstan. Their language is known as the Tatar language. As of 2010, there were an estimated 5.3 million ethnic Tatars in Russia.

While also speaking languages belonging to different Kipchak sub-groups, genetic studies have shown, that the three main groups of Tatars (Volga, Crimean, Siberian) do not have common ancestors and thus, their formation occurred independently of each other. Regarding the Crimean Tatars especially, it has been considered, whether they should even be called Tatars, citing these ethnogenetic differences. Therefore, they are also known simply as "Crimeans" (qırımlılar). A minority of Volga Tatars have tried to replace the term with "Bulgar" (or Bolgar), claiming heritage over Bulgars of Volga Bulgaria. This theory is counted as the second main theory for their formation, other being the Kipchak-theory.

Many noble families in the Tsardom of Russia and Russian Empire had Tatar origins.