Sidney Harth (Cleveland, 5 October 1925 – Pittsburgh, 15 February 2011) was an American violinist and conductor.
Harth was born in Cleveland, Ohio. He graduated from the Cleveland Institute of Music and studied with Joseph Knitzer, Mishel Boris Piastro and George Enescu. Subsequently he held faculty positions at University of Louisville, the University of Houston, the University of Texas, Yale University, and the Mannes College of Music.
He made his European debut touring France with pianist Theodore Lettvin in 1951–1952 in a concert series organized by the National Music League and the Jeunesses Musicales International. Harth performed with major orchestras across the world, and made numerous recordings with the Chicago Symphony Orchestra and the Kraków Radio and Television Orchestra.
He was Concertmaster of the New York Philharmonic Orchestra and Chicago Symphony Orchestra, Principal Concertmaster and Associate Conductor of the Los Angeles Philharmonic Orchestra, and Concertmaster and Assistant Conductor of the Louisville Orchestra. An acclaimed conductor, Harth was during his career Principal Conductor of the Natal Philharmonic Orchestra in South Africa, and Musical Director of the Jerusalem Symphony Orchestra, Northwest Chamber Orchestra of Seattle and the Puerto Rico Symphony Orchestra.