Karl Friedrich Sandhaas was a German painter and draftsman.
Sandhaas was an illegitimate son of Maria Margarete Sandhaas (1771–1830), who grew up in Haslach and moved to Darmstadt in 1816 to live with his uncle, the theater painter Josef Sandhaas.

From 1818 onwards he received lessons at the Grand Ducal Drawing School from Franz Hubert Müller. In Darmstadt he became friends with the architect Friedrich Maximilian Hessemer. Sandhaas also maintained close contacts with the artists Jakob Felsing, August Lucas and Johann Heinrich Schilbach. On March 27, 1820, at the age of 19, he enrolled in history painting at the Academy of Fine Arts in Munich.

In 1823 Sandhaas moved to Freiburg and attended the Herder'sche Kunstanstalt, which was run by the Darmstadt engraver Karl Barth. A year later, Sandhaas moved to Munich to study with Cornelius and in 1828 he came to Frankfurt, where he worked as an illustrator for the publisher E. Ullmann. From 1830, with a few interruptions, he lived in Haslach until his death.

Sandhaas preferred to work as a landscape and portrait painter; He also worked as an illustrator of literary and mythological works. As a draftsman and watercolorist, he is one of the important representatives of late romanticism in Baden.