Konstantinos "Kostas" Gavras (Greek: Κωνσταντίνος "Κώστας" Γαβράς; born 12 February 1933), known professionally as Costa-Gavras, is a Greek-French film director, screenwriter, and producer who lives and works in France. He is known for political films, such as the political thriller Z (1969), which won an Academy Award for Best Foreign Language Film, and Missing (1982), for which he won the Palme d'Or and an Academy Award for Best Adapted Screenplay. Most of his films have been made in French, but six have been in English, including Hanna K..

Costa-Gavras was born in Loutra Iraias, Arcadia. His family spent the Second World War in a village in the Peloponnese, and moved to Athens after the war. His father had been a member of the Pro-Soviet branch of the Greek Resistance, and was imprisoned during the Greek Civil War. His father's Communist Party membership made it impossible for Costa-Gavras to attend university in Greece or to be granted a visa to the United States, so after high school, he settled in France, where he began studying literature at the Sorbonne in 1951.

In 1956, he abandoned his university studies to study film at the French national film school, IDHEC. After film school, he apprenticed under Yves Allégret, and became an assistant director for Jean Giono and René Clair. After several further appointments as first assistant director, he directed his first feature film, Compartiment Tueurs, in 1965.

His 1967 film Shock Troops (Un homme de trop) was entered into the 5th Moscow International Film Festival.

In Z (1969), an investigating judge, played by Jean-Louis Trintignant, tries to uncover the truth about the murder of a prominent leftist politician, played by Yves Montand, while government officials and the military attempt to cover up their roles. The film is a fictionalised account of the events surrounding the assassination of the Greek politician Grigoris Lambrakis in 1963. It had additional resonance because, at the time of its release, Greece had been ruled for two years by the "Regime of the Colonels". Z won the Oscar for Best Foreign Language Film. Costa-Gavras and co-writer Jorge Semprún won an Edgar Award from the Mystery Writers of America for Best Film Screenplay.

L'Aveu (The Confession, 1970) follows the path of Artur London, a Czechoslovakian communist minister falsely arrested and tried for treason and espionage in the Slánský 'show trial' in 1952.

State of Siege (1972) takes place in Uruguay under the civic-military dictatorship of Uruguay in the early 1970s. In a plot loosely based on the case of US police official and alleged torture expert Dan Mitrione, an American embassy official (played by Yves Montand) is kidnapped by the Tupamaros, a radical leftist urban guerilla group, which interrogates him in order to reveal the details of secret American support for repressive regimes in Latin America.

Missing, originally released in 1982 and based on the book The Execution Of Charles Horman, concerns an American journalist, Charles Horman (played by John Shea in the film), who disappeared in the 1973 coup d'état led by General Augusto Pinochet in Chile. Horman's father, played by Jack Lemmon, and wife, played by Sissy Spacek, search in vain to determine his fate. Nathaniel Davis, US ambassador to Chile from 1971 to 1973, a version of whose character had been portrayed in the movie (under a different name), filed a US$150 million libel suit, Davis v. Costa-Gavras, 619 F. Supp. 1372 (1985), against the studio and the director, which was eventually dismissed. The film won an Oscar for Best Screenplay Adaptation and the Palme d'Or at the Cannes Film Festival (with Yılmaz Güney's movie Yol).