François Tombalbaye (Arabic: فرنسوا تومبالباي Franswā Tūmbālbāy; 15 June 1918 – 13 April 1975), also known as N'Garta Tombalbaye, was a Chadian politician who served as the first President of Chad from the country's independence in 1960 until his overthrow in 1975. A dictatorial leader, his divisive policies as president led to factional conflict and a pattern of authoritarian leadership and political instability that is still relevant in Chad today.

A native of the south of the country and a member of the Sara ethnic group, Tombalbaye began his career as a teacher during French colonial rule and joined the Chadian Progressive Party (PPT) in 1946. After serving in the colonial legislature in the 1950s, he succeeded Gabriel Lisette as the PPT's leader in 1959 and was appointed the country's first president upon gaining independence in 1960. In 1962, he declared the PPT the sole legal party and presided over a corrupt dictatorship characterized by extreme favoritism to his southern-based patronage network. In addition to his dictatorial rule, he also attempted an Africanization program that worsened the divide between the Muslim north and the Christian and animist south. In 1965, tax riots erupted into a civil war between his government and northern FROLINAT rebels. During the war, his regime was supported by France, while FROLINAT was supported by Libyan leader Muammar Gaddafi.

In 1973, he founded a new party, the National Movement for the Cultural and Social Revolution (MNRCS), changed his name to N'Garta Tombalbaye and attempted to further Africanize the country through a program of authenticité. As the civil war continued and his support in the south dwindled, particularly over his imposition of yondo, a form of ritual scarring on members of the civil service and military, he was overthrown and assassinated by members of the Chadian military during the 1975 Chadian coup d'état and replaced by Félix Malloum.

Tombalbaye was born on 15 June 1918 in the village of Bessada, in the southern region of the French colony of Chad, close to the city of Koumra. His father was a prominent trader and he was of the Sara ethnic group, the prominent ethnicity of Chad's five southern prefectures. He attended a primary school run by Protestant missionaries, in Sarh and secondary school in Brazzaville. As a young man, Tombalbaye studied to become an educator in Brazzaville, due to the lack of in-country schools.

During World War II, Tombalbaye fought for Free France against the Nazi-backed Vichy regime.

In 1946/7, Tombalbaye formed a chapter of the Chadian Progressive Party (PPT) in Sarh and rallied members of his clan and other Sara speakers to the party. After a Muslim trader mocked the Sara people as mere beasts in November 1947, he helped to direct violent protest in N'Djamena. In 1949, the French government revoked his teaching position as punishment to his involvement in political activism. A year later, he went on to direct the PPT newspaper, AEF Nouvelle, which was shut down the same year after French repression. In 1952, he won a seat in the colonial territorial assembly and was elected to French Equatorial Africa general council in 1957, where he served as vice-president. Tensions between him and Lisette grew in the late 1950s after the 1956 loi-cadre reforms where individual colonies politicians were allowed to negotiate their own constituents, rather than maintain the federation of colonies of French Equatorial Africa. He later succeeded Gabriel Lisette as head of the Chadian Progressive Party (PPT) in March 1959 after coming under pressure, heading Chad's colonial government from 1959. He ruled the country during its independence on 11 August 1960, and was appointed its first head of government.

Tombalbaye managed to create a coalition of progressive forces from both the north and south of the country and isolating the more conservative Islamic factions in the center as a colonial legislator. After independence, he adopted an autocratic form of government, eliminated opposition both within his party and outside his party by banning all other political parties. In 1963 Tombalbaye dissolved the National Assembly in response to rioting. He began nationalizing the civil service, replacing French administrators with less competent locals. He imposed a "National Loan", greatly increasing taxing, to fund the nationalization.

In October 1968, Tombalbaye was a guest of President Lyndon B. Johnson in Washington, D.C. Following brief talks with Johnson, he traveled to Texas, meeting with research scientists at ICASALS (International Center for Arid and Semiarid Land Studies), part of Texas Tech University.