Bunjevci (Serbo-Croatian: Bunjevci / Буњевци, pronounced [bǔɲeːʋtsi, bǔː-]; singular masculine: Bunjevac / Буњевац, feminine: Bunjevka / Буњевка) are a South Slavic sub-ethnic group of Croats living mostly in the region of Bačka of northern Serbia; Bács-Kiskun County (particularly in Baja and surroundings) of southern Hungary; in Croatia (Primorje-Gorski Kotar County, Lika-Senj County, Split-Dalmatia County, Osijek-Baranja County, Vukovar-Srijem County); and in Bosnia-Herzegovina. They originate from Western Herzegovina. As a result of the Ottoman conquest, some of them migrated to Dalmatia, from there to Lika and the Croatian Littoral, and in the 17th century to Bačka.

Bunjevci who remained in Bosnia and Herzegovina, as well as those in modern-day Croatia, maintain that designation chiefly as a regional identity, and declare as ethnic Croats. Those who emigrated to Bačka underwent an extensive process of integration and assimilation. In the 18th and 19th century they made up a significant part of the population of Bačka. The government of Hungary considers the Bunjevac community to be part of the Croatian minority.

Bunjevci in Serbia and Hungary are split between those who see themselves as a Croatian sub-ethnic group (bunjevački Hrvati) and those who identify themselves as a distinct ethnic group with their own language. The latter are represented in Serbia by the Bunjevac National Council, and the former by the Croat National Council.

Bunjevci are mainly Catholic and the majority still speaks neo-Shtokavian Younger Ikavian dialect of the Serbo-Croatian pluricentric language with certain archaic characteristics. Within the Bunjevac community and between Serbia and Croatia, there is an unresolved political identity conflict regarding ethnicity of Bunjevci and an ongoing language battle over the status of the Bunjevac speech as well.

Their endonym, used in Serbo-Croatian, is Bunjevci (sing. Bunjevac) (Serbo-Croatian pronunciation: [bǔɲeʋtsi]). In Hungarian their name is bunyevácok, in Dutch Boenjewatsen, and in German Bunjewatzen. According to Petar Skok they also called themselves in Bačka as Šokci (sing. Šokac), while Hungarians in Szeged also called them as Dalmát (Dalmatians; Dalmatini), which they also used for themselves in Hungary. In addition, the term meant Catholic (Croat) population from Livanjsko field up to Montenegro which was mostly considered by the neighbor Serbian Orthodox population, while at Peroj in Istria it was a pejorative name for Croats as well pobunjevčit pejoratively meant "become Catholic". In the 20th century hinterland of Novi Vinodolski, called as Krmpote, the Primorje (Littoral or Coastal) Bunjevci were economically less powerful rural population and hence it had an attribution of "otherness" with negative connotation by urban citizens. Compared to Sveti Juraj they were more powerful and refused to call themselves Bunjevci because of such broad connotation and rather used "Planinari" (Mountaineers), and the citizens name "Seljari" had negative and mockery connotation by Bunjevci. In the territory from Krmpote to Sv. Marija Magdalena in North Dalmatia there also existed multilayered regional identities Primorci and Podgorci, local Krmpoćani, while the subethnic term Bunjevci loses identity on the boundary with Velebit Podgorje.

The earliest mention of the ethnonym is argued to be in 1550 and 1561 when in Ottoman defter is recorded certain Martin Bunavacz in Baranja. However, the name was most probably erroneously transcribed (Ottoman's rarely recorded surname, being rather his father's name, which itself is possibly Dunavacz). The earliest certain mention date from the early 17th century, for example in Bačka is from 1622 when was recorded parochia detta Bunieuzi nell' arcivescovato Colociense. In Venetian Dalmatia there was Nicola Bunieuaz (1662, 1680), in Donje Moravice of Zrinski family was Manojlo Bunieuach (1670), and in Slavonia Paval Bunyevacz (1697) and Nikola Bunjevac (1698) from Bosnia. Surname became also present in Orthodox community, denoting from their perspective somebody who came from a foreign, Catholic community. The ethnonym is also mentioned by Bishop of Senj, Martin Brajković, in 1702 whose recorded folk tradition knew for the existence of five ethnic identities which constitute the population of Lika and Krbava, one of them being Catholic Vlachs also known as Bunjevci (Valachi Bunyevacz). In 1712–1714 census of Lika and Krbava was recorded only one Bunieuacz (Vid Modrich), however the military government usually used alternative term Valachi Catolici, while Luigi Ferdinando Marsili called them Meerkroaten (Littoral Croats). Alberto Fortis in Viaggio in Dalmazia ("Journey to Dalmatia") describing the Velebit (Montagne della Morlacca) recorded that the population was different from the earlier and called themselves as Bunjevci because they came from area of Buna in Bosnia and Herzegovina. 1828 writing by Colonel Ivan Murgić probably had the last original testimony of Lika-Primorje Bunjevci about their traditional identity, in which they said to be "We are hardworking brothers Bunjevci", while regarding (Catholic) confession always as "I am true Bunjevac". In general, the name came into common usage in literature and official documents only since the second half of the 18th and early 19th century.

The etymological derivation of their ethnonym is unknown. There are several theories about the origin of their name. The most common is that the name derives from the river Buna in central Herzegovina, however, although preserved in Littoral and mostly in Podunavlje branch folk oral tradition, linguists and historians generally dismiss such derivation. Another theory is that the name comes from the term Bunja, a traditional shepherd transhumance stone house in Dalmatia similar to Kažun in Istria, meaning people who live in such type of houses. Derivation from a Vlach personal name Bun/Bunj deriving from Latin name Bonifacius (with related Slavic names Bunjo, Bunjak, Bunjac, Bunac, Bunoje, Bunilo, Bunislav, Bunuš; Vlach clans of Bunčić, Bunović, and Bunuševci) is getting prominence recently. Other also propose pejorative nickname Obonjavci which is recorded since 1199 in Zadar probably meaning soldiers without order and discipline, and verb "buniti se" (to protest).

According to modern ethnological studies, Bunjevci are a South Slavic people with some elements of non-Slavic ancestry, with partial Vlach-Arbanasi anthroponymy structure (20%; also surnames of Muslim and non-Bunjevci Croatian origin shows a continuous process of assimilation of unrelated families), originating from Vlach-Croatian ethnic symbiosis of Ikavian Chakavian/Chakavian-Shtokavian language group, with some similarities to Vlach-Montenegrin symbiosis, but both being more archaic and different from the Vlach-Serbian symbiosis of Ekavian/Jekavian-Shtokavian group. Although some scholars considered them as Slavicized Vlachs, such argumentation is poorly substantiated and misunderstanding the meaning of the term Vlach, as other scholars emphasize, they were Slavs and the term Vlach in the historical context of the 16th century did not mean some distinctive Romance ethnolinguistic identity, but an Ottoman social class which mostly included people who were not of Vlachian origin in strict sense. Bunjevci were not a separate ethnic group of Vlach-Romance origin, there's no evidence they ever spoke a Romance language, designated themselves as Vlachs or considered themselves as ethnically different from near Slavic-speaking people (Croats, Bosnians and Serbs). The emergence of the identity of Bunjevci is related to the historical, social and confessional (Vlachian Orthodox Rkaći vs Vlachian Catholic Bunjevci) dichotomies and events related to the Ottoman period on the so-called Triplex Confinium (the boundary between Venetian, Ottoman, and Habsburg Empire).