Joseph Joachim (28 June 1831 – 15 August 1907) was a Hungarian violinist, conductor, composer and teacher who made an international career, based in Hanover and Berlin. A close collaborator of Johannes Brahms, he is widely regarded as one of the most significant violinists of the 19th century.

Joachim studied violin early, beginning in Buda at age five, then in Vienna and Leipzig. He made his debut in London in 1844, playing Ludwig van Beethoven's Violin Concerto, with Felix Mendelssohn conducting. He returned to London many times throughout life. After years of teaching at the Leipzig Conservatory and playing as principal violinist of the Gewandhausorchester, he moved to Weimar in 1848, where Franz Liszt established cultural life. From 1852, Joachim served at the court of Hanover, playing principal violin in the opera and conducting concerts, with months of free time in summer for concert tours. In 1853, he was invited by Robert Schumann to the Lower Rhine Music Festival, where he met Clara Schumann and Brahms, with whom he performed for years to come. In 1879, he premiered Brahms' violin concerto with Brahms as conductor. He married Amalie, an opera singer, in 1863, who gave up her career; the couple had six children.

Joachim quit service in Hanover in 1865, and the family moved to Berlin, where he was entrusted with founding and directing a new department at the Royal Conservatory, for performing music. He formed a string quartet, and kept performing chamber music on tours. His playing was recorded in 1903.