Johannes Frederik Fröhlich (or Frølich), a Danish violinist, conductor and composer, was a precursor of Niels Gade and J.P.E. Hartmann, and a central figure in Danish musical circles during the Romantic era.
He was a pupil of violinists Claus Schall and Friedrich Kuhlau. From 1827 he worked at the Royal Theatre, Copenhagen, where he was chief conductor from 1836. Fröhlich was a co-founder of the Music Society of Copenhagen and its first chairman. He wrote a symphony (in E-flat, Op. 33), and choral works and chamber music, as well as violin and piano compositions and a violin concerto. He wrote ballet music for the ballet-master and choreographer August Bournonville, founder of the Danish ballet tradition.
The main cache of his musical manuscripts is conserved in the Kongelige Bibliotek, Copenhagen.