Ignaz Jakob Holzbauer (18 September 1711 – 7 April 1783) was a composer of symphonies, concertos, operas, and chamber music, and a member of the Mannheim school. His aesthetic style is in line with that of the Sturm und Drang "movement" of German art and literature.
Holzbauer was born in Vienna. Despite the opposition of his parents, who intended him for the law, he studied music, and in 1745 became kapellmeister to Count Rottal and at the Court Theatre of Vienna. Later he was kapellmeister at Stuttgart, Germany.[1] His operas include Il figlio delle selve, which was the opening performance of the Schlosstheater Schwetzingen in 1753. Its success led to a job offer from the court at Mannheim, Germany, where he stayed for the rest of his life, continuing to compose and to teach, his students including Johann Anton Friedrich Fleischmann (1766-1798), the pianist, and Carl Stamitz. Holzbauer died in Mannheim.

His opera Günther von Schwarzburg, based on the life of the eponymous king (and described here), was an early German national opera, a performance of which Mozart and his sister attended, through which they met Anton Raaff, who was later to premiere a role in Idomeneo. This opera has recently been recorded on the label cpo. Holzbauer wrote 196 symphonies.[1]

Mozart also composed nine numbers for insertion in a Miserere by Holzbauer on commission by the Parisian Concert Spirituel in 1778, but they have been lost. They have been given the catalog number KV 297a in the list of Mozart's works.