Adolf Richard Hölzel (13 May 1853, Olmütz - 17 October 1934, Stuttgart) was a German painter. He began as a Realist, but later became an early promoter of various Modern styles, including Abstractionism.
His father was the publisher, Eduard Hölzel. In 1868, he completed a three-year apprenticeship as a typesetter at the map publishing firm of F.A.Perthes in Gotha. Three years later, he and his family moved to Vienna where, the following year he enrolled at the Academy of Fine Arts, moving to the Academy of Fine Arts, Munich, in 1876, where he studied with Wilhelm von Diez.
After completing his studies, he was married and divided his time between Munich and Rothenburg ob der Tauber. In Munich, he became acquainted with Fritz von Uhde, who introduced him to Impressionism. Together with Von Uhde, Ludwig Dill and Arthur Langhammer (1854-1901), he helped create the "Dachauer Malschule", which later became the famous artists' colony at Dachau. He lived there from 1888 to 1905 and his novel teaching methods drew students from all over Europe. In 1904, he participated in the first exhibition of the Deutscher Künstlerbund.
Already during his time in Dachau his work began moving toward abstraction, reflecting his interest in such principles as the golden section and Goethe's Theory of Colors. After studying the color theories of Wilhelm von Bezold, he developed his own color theory, based on a circle with "diatonic" and "chromatic" values (terms taken from music). He was involved in creating the Munich Secession and the Vienna Secession. His influential essay "Über Formen und Massenvertheilung" (On Shapes and Mass Distribution), was published in Ver Sacrum. After leaving Dachau, he still returned in the summer months to give private lessons.