The Việt Nam Quốc Dân Đảng (Vietnamese: [vìət naːm kwə́wk zən ɗa᷉ːŋ]; chữ Hán: 越南國民黨; lit. 'Vietnamese Nationals' Party'), also known as the Vietnamese Nationalist Party and abbreviated VNQDĐ, was a nationalist and democratic socialist political group that sought independence from French colonial rule in Vietnam during the early 20th century. Its origins lie in a group of young Hanoi-based intellectuals who began publishing revolutionary material in the mid-1920s. In 1927, after the publishing house failed because of French harassment and censorship, the VNQDĐ was formed under the leadership of Nguyễn Thái Học. Modelling itself on the Kuomintang of Nationalist China (chữ Hán: 國民黨) the VNQDĐ gained a small following among northerners, particularly teachers and intellectuals. The party, which was less successful among peasants and industrial workers, was organised in small clandestine cells.

From 1928, the VNQDĐ attracted attention through its assassinations of French officials and Vietnamese collaborators. A turning point came in February 1929 with the Bazin assassination, the killing of a French labour recruiter widely despised by local Vietnamese people. Although the perpetrators' precise affiliation was unclear, the French colonial authorities held the VNQDĐ responsible. Between 300 and 400 of the party's approximately 1,500 members were detained in the resulting crackdown. Many of the leaders were arrested, but Học managed to escape.

In late 1929, the party was weakened by an internal split. Under increasing French pressure the VNQDĐ leadership switched tactics, replacing a strategy of isolated clandestine attacks against individuals with a plan to expel the French in a single blow with a large-scale popular uprising. After stockpiling home-made weapons, the VNQDĐ launched the Yên Bái mutiny on February 10, 1930, with the aim of sparking a widespread revolt. VNQDĐ forces combined with disaffected Vietnamese troops, who mutinied against the French colonial army. The mutiny was quickly put down, with heavy French retribution. Học and other leading figures were captured and executed and the VNQDĐ never regained its political strength in the country.

Some remaining factions sought peaceful means of struggle, while other groups fled across the border to Kuomintang bases in the Yunnan province of China, where they received arms and training. Meanwhile, during the 1930s, the Ho Chi Minh's Indochinese Communist Party (ICP) began to gain followers, before being repressed following the failed 1940 Cochinchina Uprising. Vietnam was occupied by Japan during World War II and, in the chaos that followed the Japanese surrender in 1945, the VNQDĐ and the ICP briefly joined forces in the fight for Vietnamese independence. However, after a falling-out, Ho purged the VNQDĐ, leaving his communist-dominated Viet Minh unchallenged as the foremost anti-colonial militant organisation. As a part of the post-war settlement that ended the First Indochina War, Vietnam was partitioned into two zones. The remnants of the VNQDĐ fled to South Vietnam, where they remained until the Fall of Saigon in 1975 and the reunification of Vietnam under communist rule. Today, the party survives only among overseas Vietnamese.

French involvement in Vietnam started in the late 18th century when the Catholic priest Pigneau de Behaine helped Nguyễn Ánh, to found the Nguyễn dynasty by recruiting French volunteers. In return, Nguyễn Ánh, better known by his era name Gia Long, allowed Catholic missionaries to operate in Vietnam. However, relations became strained under Gia Long's successor Minh Mạng as missionaries sought to incite revolts in an attempt to enthrone a Catholic. This prompted anti-Christian edicts, and in 1858 a French invasion of Vietnam was mounted-ostensibly to protect Catholicism, but in reality for colonial purposes. The French steadily made gains and completed the colonization of Vietnam in 1883. Armed revolts against colonial rule occurred regularly, most notably through the Cần Vương movement of the late-1880s. In the early-20th century, the 1916 southern revolts and the Thái Nguyên uprising were notable disruptions to the French administration.

In late 1925, a small group of young Hanoi-based intellectuals, led by a teacher named Phạm Tuấn Tài and his brother Phạm Tuấn Lâm, started the Nam Đồng thư xã (Southeast Asia Publishing House). They aimed to promote violent revolution as a means of gaining independence for Vietnam from French colonization, and published books and brochures about Sun Yat-sen and the 1911 Revolution, as well as opening a free school to teach chữ Quốc ngữ (Vietnamese alphabet) to the working class. The group soon attracted the support of other progressive young northerners, including students and teachers led by Nguyễn Thái Học. Hoc was an alumnus of Hanoi's Commercial School, who had been stripped of a scholarship because of his mediocre academic performance. Hoc had previously tried to initiate peaceful reforms by making written submissions to the French authorities, but these were ignored, and his attempt to foster policy change through the publication of a magazine never materialized due to the refusal of a license.

Harassment and censorship imposed by the French colonial authorities led to the commercial failure of the Nam Đồng thư xã. By the autumn of 1927, the group's priorities turned towards more direct political action, in a bid to appeal to more radical elements in the north. Membership grew to around 200, distributed among 18 cells in 14 provinces across northern and central Vietnam.

At the time, nationalist sentiment had been on the increase in Vietnam. The French colonial authorities were bringing more Vietnamese into the administration, and there was a small but growing proportion who were exposed to Western education. As a result, they became aware of French ideals such as Liberté, égalité, fraternité, republicanism and democracy, which sharply contrasted to the racial inequality and stratified system of the colonial elite ruling the masses in Vietnam. There was also an increasing awareness of the political writings of Montesquieu and Jean-Jacques Rousseau, which stoked a desire for civil and political rights, combined with the knowledge of the Japanese victory over Russia in 1905 which gave people confidence that Asians could defeat western powers.