Joseph Joachim (28 June 1831 – 15 August 1907) was a Hungarian violinist, conductor, composer, and instructor who lived in Hanover and Berlin and had an international career. He is usually recognized as one of the most important violinists of the nineteenth century, working closely with Johannes Brahms.

Joachim began playing the violin at the age of five in Buda, Hungary, and continued his studies in Vienna and Leipzig. In 1844, he debuted in London, performing Beethoven's Violin Concerto under Mendelssohn's baton. Throughout his life, he returned to London several times. In 1848, he moved to Weimar, where Franz Liszt founded cultural life after years of teaching at the Leipzig Conservatory and playing as lead violinist of the Gewandhausorchester. Joachim served at the Hanoverian court from 1852, playing principal violin in the opera and directing concerts, with months of free time to go on concert tours in the summer. Robert Schumann invited him to the Lower Rhine Music Festival in 1853, where he met Clara Schumann and Brahms, with whom he would perform for years. He gave the world premiere of Brahms' violin concerto in 1879, with Brahms conducting. In 1863, he married Amalie, an opera singer who later retired; the pair had six children.

Joachim left the army in Hanover in 1865, and the family relocated to Berlin, where he was tasked with developing and managing a new performing music department at the Royal Conservatory. He formed a string quartet and continued to tour with chamber music. In 1903, his playing was recorded. The compositions of Joachim are less well-known. He assigned opus numbers to 14 compositions and created around the same amount of pieces without them. Various violin works (including three concerti) and overtures to Shakespeare's Hamlet and Henry IV are among his works. He also composed cadenzas for the concerti of several other composers (including the Beethoven and Brahms concerti). His Hungarian concerto is his most well-known composition (Violin Concerto No 2 in D minor, Op. 11).