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.