David Ernst Oppenheim (20 April 1881 – 18 February 1943) was an Austrian educator and psychologist who collaborated with Sigmund Freud and Alfred Adler.

David Ernst Oppenheim was born in Brünn, Moravia, in Austria-Hungary, to a Jewish family, and educated at the University of Vienna where he studied philology and archaeology, graduating in 1904.

Around 1909 he contacted Sigmund Freud, and in January 1910 was accepted as a member of the Vienna Psychoanalytic Association where he gave talks on the fire as a sexual symbol and on suicides at school age.

Together with Freud, he wrote a manuscript entitled “Dreams in Folklore” in 1911 which was only published in 1958, because Oppenheim left the Association and instead joined the school of Individual Psychology of Alfred Adler in 1911.

Oppenheim took part in World War I at the Italian front but later became a pacifist and an active member in the Social Democratic Party of Austria.