Horn Trio in E flat major, op. 40

The Horn Trio in E♭ major, Op. 40, by Johannes Brahms is a chamber piece in four movements written for natural horn, violin, and piano. Composed in 1865, the work commemorates the death of Brahms's mother, Christiane, earlier that year. However, it draws on a theme which Brahms had composed twelve years previously but did not publish at the time.
The work was first performed in Zurich on November 28, 1865, and was published a year later in November 1866. The Horn Trio was the last chamber piece Brahms wrote for the next eight years.