Setos (Seto: setokõsõq, setoq, Estonian: setukesed, setud) are an indigenous Finnic people and linguistic minority that have historically lived in the borderlands between modern day Estonia and Russia. Setos have historically spoken the Seto language and been Orthodox Christians. The Seto language (like Estonian and Finnish) belongs to the Finnic group of the Uralic language family. Since the early 2000s, the Setos have sought greater recognition, rather than having their language considered a dialect of Estonian. Eastern Orthodox Christianity, with influences from local folk religions is widely practiced by the Seto peoples.

The ancestral homes of many Setos can be found to the south of Lake Peipus, in the Setomaa region. After 1991 however, this territory was divided between the newly independent Estonia (Põlva and Võro counties) and the north-western sections of the Russian Federation (Pechorsky District of Pskov Oblast).

The definitive origin of the Seto people is unknown to researchers, only that they first emerged in Setomaa around the Piusa River. This was an area that was an intersection between the Finnic peoples and the Balts.

During the 13th century, the majority of Estonians along the coasts were converted to Catholicism during the Livonian Crusade led by the Teutonic Order. During this time, the majority of Setos lived under the Novgorod Republic and remained followers of their native Finnic religion. Over the next two hundred years, the Setos were converted to Orthodox Christianity due to the influence from the neighboring Slavic states, but incorporated elements of their earlier pre-Christian religion. An early prevailing belief of the origin of the Seto community was that they were ethnic Estonians who had migrated east and adopted Orthodox Christianity under the influence of the Novgorod Republic.

The cultural development of the Setos blossomed in the early 20th century when many national societies were organized. In 1905, the number of Setos reached its peak. After the proclamation of independence of Estonia, the authorities adopted a policy of Estonification of its population, which eventually led to decline of the Setos as a distinctive community within Estonia. In Russia, due to the influence of Estonian language schools, high rates of inter-community marriages, and emigration to Estonia, the number of self-identifying Setos decreased as well.

Setos are an officially protected ethnic minority in the Russian Pskov Oblast, and a linguistic minority within Estonia. In 2002, at the sixth Seto Congress the Setos declared their intent to identify as a separate people group. In a 2011 census, it was discovered that nearly two-thirds of the nearly 12,500 Seto speaking population in Estonia lived outside the historically Seto regions. This resulted in two distinct communities of Setos to emerge according to research conducted by Pille Runnel, the first being the Seto who had migrated away from Setomaa and had to recreate a communal and religious identity. The second group being the Seto people who continued to live in older communities in Setomaa.

In 1920, with the peace treaty of Tartu, the area Setomaa (Setoland) was ceded to the newly created Republic of Estonia and it was included into Petseri County. As a result of World War II, the Republic of Estonia was forcibly annexed by the Soviet Union. And on August 15, 1944, the border between the Estonian Soviet Socialist Republic and the Russian Soviet Federated Socialist Republic was revised by Moscow authorities to what it is now. The issue became topical as the Republic of Estonia was restored in the borders of the Estonian Soviet Socialist Republic in 1991, and a national border was established soon afterwards.^{[citation needed]}

In 2009, the Setos' polyphonic style of folk singing, called leelo, was added to the UNESCO list of intangible cultural heritage. Seto leelo is usually performed by women, dressed in traditional clothing. During the Seto Kingdom Day celebration, the winning lead singer of a leelo group is awarded the title Mother of Song.