Étienne Hajdú (born István Hajdú; 1907 –1996) was a Hungarian-born French sculptor of Jewish descent. Under the encouragement of his Hungarian parents, Hajdú pursued his interests in carving and, as a teenager, he trained at a Budapest vocational school in the timber industry.

After moving to Paris in the 1930s, he became part of the Hungarian circle of artists and writers. Here he studied sculpture at the studio of Emile-Antoine Bourdelle at the Académie de la grande chaumière (1927); École des arts décoratifs (1928); and École nationale supérieure des beaux-arts (1928). By 1930, inspired by an exhibition of modernist abstractionsit Fernand Léger's, Hajdú abandoned his formal education and engaged in the world of avant-garde alongside painters Maria Helena Vieira da Silva and Arpad Szenès, with whom he had his gallery debut in 1939 at the Galerie Jeanne Bucher, Paris.

He continued his studies and he further evolved during his 1940–1944 stonecutter practice in a Pyrenean marble factory which had a formative effect, and in 1944 he produced his first marble sculptures. Hajdú's sculpture was expressionist in theme, derived from the human form abstracted into volumetric outlines and pseudo-geometric shapes that cleave distinctively into their surrounding space. 

Furtheron, the  advances in technology led to experimentation in aluminum, copper, and bronze, along with welding, hammering, and riveting. 

Étienne Hajdu had his first solo exhibition at the Galerie Jeanne Bucher in Paris in 1946, and his works were also exhibited at the Salon de Mai in Paris in 1947 and in other exhibitions in Paris, Tokyo, New York, and other cities throughout the 1950s and 1960s. His sculptures were introduced to American audiences through The New Decade: 22 European Painters and Sculptors exhibition at the Museum of Modern Art in New York in 1955, and he received his New York gallery debut at M. Knoedler & Company in 1958. A retrospective of his work was mounted by the Musée des beaux-arts in Dijon, France in 1978, and it traveled to the Műcsarnok in Budapest and the Muzeul Naţional de Artă al României in Bucharest. The French Ministry of Culture awarded him the Grand Prix National de Sculpture in 1969.