Karl Gottlieb Bretschneider was a German Protestant scholar and theologian from Gersdorf, Saxony. He is noted for, among other things, having planned and founded the monumental Corpus Reformatorum. He is the father of Carl Anton Bretschneider, a mathematician.

Karl or Carl Gottlob Zumpt was a German classical scholar known for his work in the field of Latin philology.

Karl Groos was a German philosopher and psychologist who proposed an evolutionary instrumentalist theory of play. His 1898 book on The Play of Animals suggested that play is a preparation for later life.

Heinrich Karl Grünberg was a German communist writer and journalist.

Karl Gustaf Andresen was a German linguist. He was the father of Romance philologist Hugo Andresen (1844–1918).

Karl Ferdinand Gutzkow was a German writer notable in the Young Germany movement of the mid-19th century.

Karl Hans Strobl was an Austrian author and editor. Strobl is best known for his horror and fantasy writings. Strobl was a member of the Nazi Party.

Karl Heinrich Heydenreich was a German philosopher and poet.

Karl Heinrich Ritter von Lang was a German historian and statesman.

Karl Heinrich Rau (23 November 1792 – 18 March 1870) was a German political economist.