Michel Jean-Pierre Debré (French pronunciation: ​[miʃɛl dəbʁe]; 15 January 1912 – 2 August 1996) was the first Prime Minister of the French Fifth Republic. He is considered the "father" of the current Constitution of France. He served under President Charles de Gaulle from 1959 to 1962. In terms of political personality, he was intense and immovable, with a tendency to rhetorical extremism.

He studied at the Lycée Montaigne and then at the Lycée Louis-le-Grand, obtained a diploma from the École Libre des Sciences Politiques, and a Ph.D. in Law from the University of Paris. He then became a Professor of Law at the University of Paris. He also joined the École des Officiers de Réserve de la Cavalerie (Reserve Cavalry-Officers School) in Saumur. In 1934, at the age of twenty-two, Debré passed the entrance exam and became a member of the Conseil d'État. In 1938, he joined the staff of the Economy Minister Paul Reynaud.

Michel Debré had four sons: Vincent Debré (1939–), businessman; François Debré (1942–), journalist; Bernard Debré (born in 1944), urologist and politician; and his fraternal twin, Jean-Louis Debré, Politician. See Debré family.

During the summer of 1943, General Charles de Gaulle gave Debré the task of making a list of prefects, or State representatives, who would replace those of the Vichy regime after the liberation. In August 1944 de Gaulle made him Commissaire de la République for Angers, and in 1945, the Provisional Government charged him with the task of reforming the French Civil Service. Debré created the École nationale d'administration, whose idea was formulated by Jean Zay before the war.

To justify the departmentalization of the island that occurred in 1946 and to preserve its inhabitants from the temptation of independence, Debré implemented an economic development policy, and opened the island's first family planning center. He personally fought to get Paris to create a second high school on the south of the island, in Le Tampon, when at the time there was only one, the Lycée Leconte-de-Lisle, that catered for many thousands of inhabitants.

Under the Fourth Republic, Michel Debré at first supported the Democratic and Socialist Union of the Resistance, but defected to the Radical-Socialist Party on the advice of General Charles de Gaulle, who reportedly told him and several other politicians, including Jacques Chaban-Delmas,"Allez au parti radical. C'est là que vous trouverez les derniers vestiges du sens de l'Etat" – "Go to the radical party. It is there that you will find the last vestiges of the meaning of the state". He then joined the Rally of the French People and was elected senator of Indre-et-Loire, a position he held from 1948 to 1958. In 1957, he founded Le Courrier de la colère, a newspaper that fiercely defended French Algeria and called for the return to power of de Gaulle. In the 2 December 1957 issue, Debré wrote:

Michel Debré became the Garde des Sceaux (Minister of Justice) in the cabinet of General de Gaulle on 1 June 1958. He played an important role in drafting the Constitution of the Fifth Republic, and on its acceptance he took up the new position of Prime Minister of France, which he held from 8 January 1959 to 1962.

After the 1962 Évian Accords referendum that ended the Algerian War and gave auto-determination to Algeria was approved by a nearly ten-to-one margin, de Gaulle replaced him with Georges Pompidou. In November, during the parliamentary elections that followed the dissolution of the National Assembly, he tried to be elected Député for Indre-et-Loire. Defeated, in March 1963 he decided to go to Réunion, an island he had visited for less than twenty-four hours on 10 July 1959 when on a trip with President de Gaulle. This choice reflects Debré's fear that what remained of the French colonial empires would follow the path trodden by Algeria – that of independence, towards which he was not sympathetic. Debré wanted to take action against the Communist Party of Réunion that had been founded by Paul Vergès a few years earlier. The movement sought self-determination for the island and the removal of its position as an overseas department, and had staged demonstrations on the island a few day earlier. He also noted that the invalidation of Gabriel Macé's election as Mayor of Saint-Denis rendered the post open to the opposition, so he took the decision to win over this mandate.

Michel Debré arrived on the island of Réunion in April 1963, and succeeded in being elected Député for Saint-Denis on 6 May despite local opposition to the Ordonnance Debré law he had introduced in 1960, that allowed civil servants in the overseas departments and territories of France to be recalled to Metropolitan France if suspected of disturbing public order. Supported by those who rejected autonomy, he immediately became the leader of the local right-wing. This state of affairs would be challenged by Pierre Lagourgue that during the next decade.

He returned in the government in 1966 as Economy and Finance Minister. After the May 1968 crisis, he became Foreign Minister, then, one year later, he served as Defence Minister of President Georges Pompidou. In that role, he became a hated figure of the left, because of his determination to expropriate the land of 107 peasant farmers and Shepherds on the Larzac plateau, to extend an existing military base. The resulting civil disobedience campaign was ultimately victorious. Considered as a guardian of the Gaullist orthodoxy, he was marginalized after the election of Valéry Giscard d'Estaing as President of France in 1974. He criticized with virulence his foreign policy. In 1979 he took a major part in the Rally for the Republic (RPR) campaign against the European federalism and was elected member of the European Parliament in order to defend the principle of Europe of nations. But later, he accused Jacques Chirac and the RPR lead to moderate their speech, and so, he was a dissident candidate in the 1981 presidential election. He obtained only 1.6% of votes.

For a period of around two decades in the twentieth century (1968-1982), 1,630 children from Réunion were relocated to France, particularly to Creuse. These children, known as Les enfants de la Creuse, were brought to light in 2002 when Réunion exile Jean-Jacques Martial made a legal complaint against Politician Michel Debré (who organized the controversial displacement) for "kidnapping of a minor, roundup and deportation". In 2005, a similar case was brought against the French Government by the Association of Réunion of Creuse.