Oskar Ewald (; born Oskar Friedländer; 11 November 1881, Búrszentgyörgy/Sankt Georgen, Hungary (now Borský Svätý Jur, Senica District, Slovakia) â 25 September 1940, near Oxford, Oxfordshire) was a Hungarian-Austrian philosopher.
His father was Moritz Friedländer, a liberal scholar of Judaism who worked with the Jewish community of the Kingdom of Hungary on matters including the expansion of education.
Beginning in 1901, Ewald was a member of a group of young intellectuals in Vienna, Die Männer der Zukunft. In addition to Ewald, this group included Otto Weininger, Arthur Gerber, , , and .
Ewald converted to Protestantism and changed his last name to Ewald.