The uprising of 1821 was a social and political rebellion in Wallachia, which was at the time a tributary state of the Ottoman Empire. It originated as a movement against the Phanariote administration, with backing from the more conservative boyars, but mutated into an attempted removal of the boyar class. Though not directed against Ottoman rule, the revolt espoused an early version of Romanian nationalism, and is described by historians as the first major event of a national awakening. The revolutionary force was centered on a group of Pandur (light infantry) irregulars, whose leader was Tudor Vladimirescu. The center of the uprising was the Wallachian subregion of Oltenia, where Vladimirescu established his "Assembly of the People" in February.

From the beginning, Pandurs were joined by groups of Arnauts and by veterans of the Serbian Revolution. Although infused with anti-Hellenism, they collaborated with, and were infiltrated by, agents of the Filiki Eteria. Vladimirescu also cooperated with the Sacred Band of Alexander Ypsilantis, thereby contributing to the larger war of Greek independence. In conjunction with Ypsilantis' troops coming in from Moldavia, Vladimirescu managed to occupy Bucharest in March. Vladimirescu agreed to split the country with Ypsilantis, preserving control over Oltenia, Bucharest, and the southern half of Muntenia. The Pandurs' relationship with the Sacred Band degenerated rapidly, upon revelations that the Russian Empire had not validated Ypsilantis' expedition, and also over Vladimirescu's attempts to quell Eterist violence. Many of the Arnauts openly or covertly supported Ypsilantis, while others endorsed an independent warlord, Sava Fochianos.

Vladimirescu secretly negotiated an entente with the Ottomans, who ultimately invaded Wallachia in late April. The Pandurs withdrew toward Oltenia, which put them at odds with the Sacred Band. Vladimirescu's brutality alienated his own troops; in turn, this rift allowed the Greek revolutionaries to arrest and execute Vladimirescu, unopposed. The Oltenians scattered, though some Pandurs formed pockets of resistance, led by captains such as Dimitrie Macedonski and Ioan Solomon. They suffered clear defeat in their confrontation with the Ottoman Army. In June, Ypsilantis' force and its remaining Pandur allies were routed at Drăgășani. The uprising sparked a cycle of repressive terror, with a final episode in August, when Fochianos and his Arnauts were massacred in Bucharest.

The uprising of 1821 is widely seen as a failed or incomplete social revolution, with more far-reaching political and cultural implications. The Ottoman government registered its anti-Phanariote message, appointing an assimilated boyar, Grigore IV Ghica, as Prince of Wallachia. The ascent of nationalist boyars was enhanced during the Russian occupation of 1828, and cemented by a new constitutional arrangement, Regulamentul Organic. During this interval, survivors of the uprising split between those who supported this conservative establishment and those who favored liberal causes. The latter also helped preserve a heroic image of Vladimirescu, which was later also borrowed by agrarianists and left-wing activists.

From the beginning of the 18th century, Wallachia and Moldavia (the Danubian Principalities) had been placed by the Sublime Porte under a regime of indirect rule through Phanariotes. This cluster of Greek and Hellenized families, and the associated Greek diaspora, were conspicuously present at all levels of government. At a more generalized level, the Phanariote era emphasized tensions between the boyars, Phanariote or not, and the peasant class. Though released from serfdom, Wallachian peasants were still required to provide for the boyars in corvées and tithes. Over the early 19th century, the rural economy was often paralyzed by peasant strikes, tax resistance, sabotage, or litigation. Additional pressures were created by Ottoman demands for the haraç and other fiscal duties, which the Phanariotes fulfilled through tax farming. "Excessive fiscal policies, dictated by both the Ottoman demands and the short span of reigns" meant that Phanariotes treated the principalities as "an actual tenancy." The national budget for 1819 was 5.9 million thaler, of which at least 2 million were taken by the Sublime Porte, 1.3 million went to the ruling family, and 2.4 supplied the bureaucracy. Although not at their highest historical level, Ottoman pressures had been steadily increasing since ca. 1800.

Tax payers were additionally constrained by those boyars who obtained tax privileges or exemptions for themselves and their families. In 1819, from 194,000 families subject to taxation, 76,000 had been wholly or partly exempted. Tax farmers, in particular the Ispravnici, acted in an increasingly predatory manner, and, in various cases, tortured peasants into paying more than their share. In the 1800s, a reformist Prince Constantine Ypsilantis sided with the peasants, cracking down on abuse and even threatening capital punishment; this episode failed to address the causes, and abuses continued to be recorded into the 1810s. Under constant fiscal pressure, many villagers resorted to selling their labor to boyars or to peasant entrepreneurs. According to a report by the Ispravnic of Gorj County, in 1819 migrant farmhands could barely cover their tax debt.

Under the Phanariote regime, the country had dissolved her levy army—though a core force had briefly reemerged under Nicholas Mavrogenes, who led a Wallachian peasant force into the Austro-Turkish War of 1788. Especially visible in Oltenia, the Pandurs traced their origins to the late 17th century, and had also functioned as a militia in 1718–1739, when Oltenia, or "Banat of Craiova", was a Habsburg territory. At times, they had been self-sustaining, with a lifestyle that bordered on hajduk brigandage. The Phanariotes' hold on the country was put into question by turmoil during the Napoleonic era, which resulted in some additional rearmament. In 1802, the threat of an invasion by Ottoman secessionist Osman Pazvantoğlu pushed Bucharest into a panic. At its height, the mercenary Sava Fochianos and his Arnauts denounced their contract and left the city defenseless. This embarrassment prompted Ypsilantis to form a small national contingent, comprising armed burghers and Pandurs who were trained by Western standards.

Although approved by the Ottomans, this new militia was secretly also a component of Ypsilantis' plan to shake off Ottoman suzerainty with help from the Russian Empire. By August 1806, his alliance with Russia had been exposed, and he was forced to leave into exile. The incident also sparked a six-year-long Russo-Turkish War. During this period, the Wallachian Pandurs, including a young Tudor Vladimirescu, acted as a unit of the Imperial Russian Army. Under Russian occupation, the Greek–Wallachian rebel Nicolae Pangal issued several manifestos which, as noted by historian Emil Vârtosu, resembled later appeals by Vladimirescu.