Ignaz Lachner (11 September 1807 – 24 February 1895) was a German composer and conductor.

From 1853, Lachner served as a Kapellmeister in Hamburg and moved into the same position again in 1861 at the Stadttheater in Frankfurt, from which he retired in 1875.

Although primarily known as a conductor, Lachner composed a considerable amount of music in almost every genre.

Among his best known and most successful compositions was his Alpine Scenes, Das letzte Fensterln, although critics, such as Wilhelm Altmann, today generally consider his chamber music to be his best work.

Of these, his six trios for the unusual combination of violin, viola and piano were among the best ever written for this combination and his seven string quartets achieved considerable popularity in their time by virtue of their fetching melodies and effective harmonies.