Ernst von Dohnányi (Hungarian: Dohnányi Ernő, [ˈɛrnøː ˈdohnaːɲi]; 27 July 1877 – 9 February 1960) was a Hungarian composer, pianist and conductor. He used a German form of his name on most published compositions.

Dohnányi's composing style was personal, but very conservative. His music largely subscribes to the romantic idiom. Although he used elements of Hungarian folk music, he is not seen to draw on folk traditions in the way that Bartók or Kodály do. Some characterize his style as traditional mainstream Euro-Germanic in the Brahmsian manner (structurally more than in the way the music actually sounds) rather than specifically Hungarian, while others hear very little of Brahms in his music. The very best of his works may be his Serenade in C major for string trio, Op. 10 (1902) and Variations on a Nursery Tune for piano and orchestra, Op. 25 (1914). His Second symphony is a major work which he composed during the Second World War. It is uncharacteristically sombre, notably in the third movement, which is grotesque and dissonant.