Károly Aggházy in Hungarian pronounced as /ˈkaːroj ˈɒkhaːzi/ (30 October 1855, Budapest – 8 October 1918, Budapest) was a Hungarian piano virtuoso and composer.
Aggházy was a pupil of Robert Volkmann, Anton Bruckner, and Franz Liszt. He later taught at the National Conservatory in Budapest. Besides several operas, most notably Maritta (1895), he chiefly wrote chamber music and pieces for piano. He died in Budapest at age 62.