The Symphony No. 3 in E♭ major, Op. 55, (also Italian Sinfonia Eroica, Heroic Symphony) is a symphony in four movements by Ludwig van Beethoven. One of the composer's most celebrated works, the Eroica symphony is a large-scale composition that marked the beginning of Beethoven's creative middle-period.

Composed mainly in 1803–1804, the work is grounded in the Classical symphonic tradition while also stretching boundaries of form, length, harmony, and perceived emotional and possibly cultural content. It has therefore widely been considered an important landmark in the transition between the Classical period and the Romantic era.