Johann Baptist Strauss II (German: [ˈjoːhan bapˈtɪst ˈʃtʁaʊs]; 25 October 1825 – 3 June 1899), also known as Johann Strauss Jr., the Younger or the Son (German: Johann Strauß Sohn), was an Austrian composer of light music, particularly dance music and operettas as well as a violinist. He composed over 500 waltzes, polkas, quadrilles, and other types of dance music, as well as several operettas and a ballet. In his lifetime, he was known as "The Waltz King", and was largely responsible for the popularity of the waltz in Vienna during the 19th century. Some of Johann Strauss's most famous works include "The Blue Danube", "Kaiser-Walzer" (Emperor Waltz), "Tales from the Vienna Woods", "Frühlingsstimmen", and the "Tritsch-Tratsch-Polka". Among his operettas, Die Fledermaus and Der Zigeunerbaron are the best known.

Strauss was the son of Johann Strauss I and his first wife Maria Anna Streim. Two younger brothers, Josef and Eduard Strauss, also became composers of light music, although they were never as well known as their brother.