Alexander Winterberger (14 August 1834 – 23 September 1914) was a German organist and composer. He is mostly remembered for his association with Franz Liszt, in particular his close involvement with the two great organ fantasies Liszt wrote for the Merseburg Cathedral organ, the Fantasy and Fugue on the chorale "Ad nos ad salutarem undam" and the Fantasy and Fugue on the Theme B-A-C-H.
Alexander Winterberger was born in 1834. He studied at Weimar with the Weimar Municipal Organist Johann Gottfried Töpfer (1791-1870).
Although he also studied under Franz Liszt until 1853, he was in the 'outer circle' of students, that is, not among those with whom Liszt spent most time and was on most intimate personal terms. He displayed a mastery of novel registrations, which in some cases Liszt and he worked out together. Winterberger had been a classmate of Julius Reubke in Berlin, and he was instrumental in Reubke deciding to come to Weimar to study with Liszt.
In 1855 Liszt inspected the construction of the new organ at Merseburg Cathedral, and resolved to write (some sources say he was commissioned by Winterberger) a grand piece for the official opening: his Fantasy and Fugue on the Theme B-A-C-H. The date was set for 26 September 1855, but by 22 September the Fantasy was still not ready. Instead, he decided to have Winterberger premiere the revised version of the Fantasy and Fugue on the chorale "Ad nos ad salutarem undam" (it had been published in 1852, but Liszt revised it more than once, most recently in 1855). They rehearsed the work together a few days before the official opening.
The B-A-C-H Fantasy and Fugue, dedicated to Winterberger, finally had its premiere on 13 May 1856, again at Merseburg Cathedral. On the same occasion Winterberger also played Liszt's arrangement of the Church Festive Overture on the Chorale "A Mighty Fortress (Ein feste Burg)" by Otto Nicolai.