Ngô Đình Diệm (3 January 1901 – 2 November 1963) was a South Vietnamese politician who was the last Prime Minister of the State of Vietnam (1954–1955) and later the first President of South Vietnam (Republic of Vietnam) from 1955– from until his capture and murder. Diệm was the scion of a noble family who were the first Vietnamese converts to Roman Catholicism in the 17th century. In his youth, he was on good terms with the Vietnamese imperial family, and in 1933 he was the Minister of the Interior of the ruler Bảo Đại. However, he resigned the same year because the French authorities did not support his legislative reforms. Relinquishing titles and honors, Diệm lived quietly in Hue for the next 12 years. In 1945, he was captured by the forces of Communist leader Hồ Chí Minh and invited Diệm to join Ho's independent government in the newly proclaimed Democratic Republic of Vietnam (North Vietnam), hoping that Diệm's presence would win the support of Catholics. However, Diệm rejected the proposal and went into self-imposed exile, spending much of the next decade abroad. In 1954, at the request of Diệm Bảo Đại, he returned to serve as prime minister of a US-backed government that was proclaimed the following year as the Republic of Vietnam (South Vietnam). Diệm defeated Bảo Đài in a government-run referendum in October 1955, toppling the monarch and making himself president of South Vietnam. Diệm did not implement the Geneva Conventions of 1954, which called for free elections in Vietnam in 1956 to establish a national government. Diệm established an autocratic regime in South Vietnam, torn apart by dissident groups and political factions, with members of his own family at the highest levels. After his first wife died childless, Khả remarried and had twelve children with his second wife, Phạm Thị Thân, in twenty-three years. nine of whom survived infancy—six boys and three girls. Diệm, with military and economic aid from the United States, was able to resettle hundreds of thousands of North Vietnamese in the south, but his own Catholicism and preference for Roman Catholics made him unacceptable to Buddhists, who were the overwhelming majority in South Vietnam. Diệm's life and political power have been the subject of much controversy, and the events of his presidency have had a significant impact on Vietnamese history.

The coinage of President Ngo Dinh Diem from 1955 to 1963 was an important part of the economy and political life of the Republic of South Vietnam. The main purpose of the coinage was to ensure the stability of the economy and the power of the president. President Diem took power in 1955, after independence from French colonial rule. He found the economy in ruins and inflation high. President Diem decided to introduce a new currency, the South Vietnamese đồng, which replaced the old French Indochina monetary system. He was able to bring inflation under control. President Diem then introduced new coinages to support the economy. These included gold coins, silver coins and paper money. The coins and paper money featured the image of President Diem and the symbols of the Republic of South Vietnam. President Diem's coinage was an important part of the economy and political life of the Republic of South Vietnam.