Olga Milles (Olga Louise Granner; Graz, 1874 - Graz, 1967) was an Austrian portrait painter who spent much of her married life in Sweden as the wife of the sculptor Carl Milles. Her career shows how a painter with solid training could move into the background after marriage.
She trained in Graz at the Landschaftliche Zeichenakademie, then at Anton Ažbe's school in Munich (1893-1895) and at the Académie Colarossi in Paris. Her commissioned portraits of the Austrian aristocracy supported her financially, and around 1900 she exhibited in Vienna, Munich and Graz.
She married Carl Milles in 1905, a union generally regarded as platonic. In 1906 the couple settled at Millesgården on the island of Lidingö, and in 1931 they moved to Detroit, where he taught at the Cranbrook Academy of Art. There she painted portraits while managing the household, though few of her works survive, possibly because she destroyed many of her own paintings.
After her husband's death in 1955 she returned to Graz, where she died in 1967. Her ashes rest in the chapel at Millesgården, beside his.