Wilhelm Backhaus ('Bachaus' on some record labels) (26 March 1884 – 5 July 1969) was a German pianist and pedagogue. He was particularly well known for his interpretations of Mozart, Beethoven, Schumann, Chopin and Brahms. He was also much admired as a chamber musician.

Born in Leipzig, Backhaus was the son of a well-known architect. He began learning piano at the age of four with his mother, an amateur pianist. The boy's talent was soon recognized by Arthur Nikisch, at whose recommendation Backhaus studied under Alois Reckendorf at the Leipzig Conservatory between 1891 and 1899, then took private piano lessons with Eugen d'Albert in Frankfurt. As a boy of 9 or 10 he was taken to hear both of the Brahms piano concertos performed by d'Albert — and conducted by Brahms himself.

He made his first concert tour at the age of sixteen. In 1900 he went to England and in 1901 played for the first time in Manchester at the Gentleman's Concerts. In 1902 he performed at the Hallé Concerts, and thereafter in 12 concerts at the Queen's Hall, London, and played 6 different piano concertos at the Promenade Concerts. In 1904 he became Professor of Piano at the Royal Manchester College of Music. In 1905 he won the Anton Rubinstein Competition, with Béla Bartók taking second place. He toured widely throughout his life - in 1921 he gave seventeen concerts in Buenos Aires in less than three weeks. Backhaus made his U.S. debut on 5 January 1912 as soloist in Beethoven's 5th Piano Concerto (the "Emperor") with Walter Damrosch and the New York Symphony Orchestra.He taught at the Curtis Institute of Music in 1926. In 1930, he moved to Lugano and became a citizen of Switzerland. He died in Villach in Austria, where he was due to play in a concert. His last recital a few days earlier in Ossiach was recorded.