The Hungarian minority of Romania (Hungarian: romániai magyarok, pronounced [ˈromaːnijɒji ˈmɒɟɒrok]; Romanian: maghiarii din România) is the largest ethnic minority in Romania. As per the 2021 Romanian census, 1,002,151 people (6% of respondents) declared themselves Hungarian, while 1,038,806 people (6.3% of respondents) stated that Hungarian was their mother tongue.

Most ethnic Hungarians of Romania live in areas that were parts of Hungary before the Treaty of Trianon of 1920. Encompassed in a region known as Transylvania, the most prominent of these areas is known generally as Székely Land (Romanian: Ținutul Secuiesc; Hungarian: Székelyföld), where Hungarians comprise the majority of the population. Transylvania, in the larger sense, also includes the historic regions of Banat, Crișana and Maramureș. There are forty-one counties of Romania; Hungarians form a large majority of the population in the counties of Harghita (85.21%) and Covasna (73.74%), and a large percentage in Mureș (38.09%), Satu Mare (34.65%), Bihor (25.27%), Sălaj (23.35%), and Cluj (15.93%) counties.

There also is a community of Hungarians living mostly in Moldavia, known as the Csángós. These live in the so-called region of Csángó Land in Moldavia but also in parts of Transylvania and in a village of Northern Dobruja known as Oituz. In addition, sparse populations of Székelys are to be found across southern Bukovina, inhabiting several villages and communes in Suceava County. Aside from the aforementioned historical regions of Romania, Bucharest was also home in the past and still is to a sizable Hungarian-Romanian community.

The Hungarian tribes originated in the vicinity of the Ural Mountains and arrived in the territory formed by present-day Romania during the 9th century from Etelköz or Atelkuzu (roughly the space occupied by the present day Southern Ukraine, the Republic of Moldova and the Romanian province of Moldavia). Due to various circumstances (see Honfoglalás), the Magyar tribes crossed the Carpathians around 895 AD and occupied the Carpathian Basin (including present-day Transylvania) without significant resistance from the local populace. The precise date of the conquest of Transylvania is not known; the earliest Magyar artifacts found in the region are dated to the first half of the 10th century.

In 1526, at the Battle of Mohács, the forces of the Ottoman Empire annihilated the Hungarian army and in 1571 Transylvania became an autonomous state, under the Ottoman suzerainty. The Principality of Transylvania was governed by its princes and its parliament (Diet). The Transylvanian Diet consisted of three Estates (Unio Trium Nationum): the Hungarian nobility (largely ethnic Hungarian nobility and clergy); the leaders of Transylvanian Saxons-German burghers; and the free Székely Hungarians.

With the defeat of the Ottomans at the Battle of Vienna in 1683, the Habsburg monarchy gradually began to impose their rule on the formerly autonomous Transylvania. From 1711 onward, after the conclusion of Rákóczi's War for Independence, Habsburg control over Transylvania was consolidated, and the princes of Transylvania were replaced with Habsburg imperial governors. In 1765 the Grand Principality of Transylvania was proclaimed, consolidating the special separate status of Transylvania within the Habsburg Empire, established by the Diploma Leopoldinum in 1691. The Hungarian historiography sees this as a mere formality. Within the Habsburg Empire, Transylvania was administratively part of Kingdom of Hungary.

After the Austro-Hungarian Compromise of 1867, Transylvania became an integral part of the Kingdom of Hungary again, with Hungarian becoming the official language and Magyarization being introduced in the region not soon after.

Following defeat in World War I, Austria-Hungary disintegrated. The ethnic Romanian elected representatives of Transylvania, Banat, Crișana, and Maramureș proclaimed Union with Romania on 1 December 1918. With the conclusion of World War I and the Hungarian–Romanian War (1918–1919), the Treaty of Trianon (signed on 4 June 1920) defined the new border between the states of Hungary and Romania. As a result, the more than 1.5 million Hungarian minority of Transylvania found itself becoming a minority group within Romania. Also after World War I, a group of Csángó families founded a village in Northern Dobruja known as Oituz, where Hungarians still live today.