Julius Ruthardt (December 13, 1841 – October 13, 1909) was a German violinist and composer.
Born in Stuttgart to Friedrich Ruthardt, an oboist and composer, the younger Ruthardt became a violinist in the Stuttgart court orchestra at a young age in 1855, then Kapellmeister at the theatre in Riga from 1871 and in Leipzig from 1882. He also composed incidental music for Bjørnstjerne Bjørnson's Halte-Hulda.