Johann Adam Hiller (born Dec. 25, 1728, Wendisch-Ossig, near Görlitz, Saxony [Germany]—died June 16, 1804, Leipzig) was a German composer and conductor, regarded as the creator of the German singspiel, a musical genre combining spoken dialogue and popular song.

Hiller learned to play several instruments and to sing and also briefly studied law while developing wide intellectual and literary interests. After varied activities in the musical life of Leipzig, including the production of many vocal compositions and writings about music, he became conductor (1781–85) of the Gewandhaus concerts and the town’s leading musical figure. He also started a singing school. After an ill-fated move to a court position in Courland, he returned to Leipzig, becoming from 1789 to 1800 the cantor of the Thomasschule, a position formerly held by J.S. Bach.

With his singspiels Hiller gave Germany its first national operettas, which quickly became popular. Die Liebe auf dem Lande (1768; “Love of the Land”) and Die Jagd (1770; “The Hunt”) rank among the finest of his many works in the form. He also wrote numerous songs and church music.