Elin Kleopatra Danielson-Gambogi was a Finnish painter, best known for her realist works and portraits. Danielson-Gambogi was part of the first generation of Finnish women artists who received professional education in art, the so-called "painter sisters' generation". The group also included Helene Schjerfbeck (1862–1946).

Elin Danielson was born in the small village of Noormarkku, near the city of Pori in Western Finland to Karl Danielson and Rosa Amalia Danielson. Her early years were however spent at Ilmajoki as her father attempted farming there. Because of the Finnish famine of 1866–68, the farm failed. After being forced to sell the farm, her father Karl shot himself. Her mother Rosa returned to Noormarkku with her two daughters.

At the age of 15, Danielson moved to Helsinki and began studying in the Academy of Fine Arts where her teachers included Carl Eneas Sjöstrand and Hjalmar Munsterhjelm. In 1878, Danielson started courses with Adolf von Becker.

In 1883 Danielson moved to Paris and took lessons at the Académie Colarossi under Gustave Courtois and painted in Brittany during the summertime. A few years later she returned to Finland and lived with her relatives in Noormarkku and Pori. In 1888 she opened an atelier in Noormarkku. During the 1880s and 1890s she also worked as a teacher in several art schools around Finland.

In 1895, she received a scholarship and traveled to Florence, Italy. A year later she moved to the village of Antignano in Livorno where she met an Italian painter 13 years younger, Raffaello Gambogi (1874–1943). They began working together and got married in 1898. They held exhibitions in Paris, Florence (where she was awarded an art prize by the city) and Milan and in many Finnish cities, and their paintings were also included in the 1900 World's Fair in Paris, where she again won bronze medal. She also got to second place at the 1901 national portrait painting competition organized by the Finnish state. King Umberto even purchased a painting from her.

Their marriage was strained when Raffaello fell in love with Danielson's Finnish friend Dora Wahlroos. She moved to Finland for a while, but returned in 1903. Because of World War I, her connection to her home land was cut, and by the time she died of pneumonia at Antignano in 1919, she had been mostly forgotten in Finland.