Johannes Daniel Falk (28 October 1768 – 14 February 1826) was a German poet.
Falk was born in Danzig (Gdańsk) in the Polish province of Royal Prussia. In 1816 he wrote the German text O Du Fröhliche.. to the melody of one of the most popular Christmas songs, O Sanctissima. Falk was the founder of the Falk'sche Institute, a public education place for orphans in Weimar. He died in that city in 1826.