Oskar Frenzel (12 November 1855 – 15 May 1915) was a German landscape-artist, animal painter and lithographer.

He became an animal and landscape painter in addition to his work as a lithographer from 1879 in the evening classes of the teaching institute of Museum of Decorative Arts Berlin.

Between 1884 and 1889, he studied at the Prussian Academy of Arts in Berlin under Paul Friedrich Meyerheim and Eugen Bracht.

With his colleague Paul Müller-Kaempff in 1889 he "discovered" the fishing village of Ahrenshoop on the Baltic Sea, where an artists' colony emerged in the following years.

In 1902 he joined the Secession again and was from 1904 until his death a member of the Prussian Academy of Arts.