August Harder (17 July 1775 – 22 October 1813) was a German musician, composer and writer.

He is known for the melody to Paul Gerhardt's sacred summer song "Geh aus, mein Herz, und suche Freud".

Born Augustin Harder in Schönerstädt near Leisnig, Saxony, he grew up as the son of the village teacher, receiving the first music lessons from his father.

He worked as a freelance musician, as singer, pianist, guitarist, also as a composer, writer and teacher.

[1] Harder composed singable melodies, of which the one to Paul Gerhardt's sacred summer song "Geh aus, mein Herz, und suche Freud" was of lasting popularity.