Katherine Sophie Dreier (September 10, 1877 – March 29, 1952) was an American artist, lecturer, patron of the arts, and social reformer.

She was most influenced by modern art, particularly by her friend Marcel Duchamp, and due to her frustration with the poor reception that the works received, she became a supporter of other artists.

Dreier was also an active suffragette, attending the sixth convention of the International Woman Suffrage Alliance in Stockholm, Sweden as a delegate.

She was the head of the New York City's German-American Committee of the Woman Suffrage party in 1915 and treasurer of the organization her mother established, German House for Recreation of Women and Children.

Theodor came to the United States in 1849 and became partner of the English iron firm of Naylor, Benson and Company's New York branch.

He married Dorothea in 1864 during a visit to Bremen, brought her back with him to the United States, and they lived in a brownstone house in Brooklyn Heights, New York.

[2] Dreier took art lessons each week when she was 12 years of age and she attended George Brackett, a private school in Brooklyn.

[2] By 1900 her mother founded the German House for Recreation of Women and Children, where Katherine was treasurer on a volunteer basis from 1900 to 1909.

[4][6] A suffragette, she was involved in the International Woman Suffrage Alliance, attending its sixth convention in Stockholm, Sweden in 1911 as a delegate.

When she returned, Dreier had private lessons from painter Walter Shirlaw, who gave her a great foundation in the fundamentals of art and encouraged individual expression.

[4] She moved to Chelsea, London, England in 1909, living in a neighborhood that had been associated with Oscar Wilde and James Abbott McNeill Whistler.

[4] Dreier returned to London to marry Edward Trumball in August 1911, but was back in England by September, and her marriage was annulled.

It promoted the works of Paul Klee, Stanton Macdonald-Wright, Wassily Kandinsky, Heinrich Campendonk, Joan Miró, David Burliuk, Kazimir Malevich and Fernand Léger.

The Société held the first permanent collection of modern art in the United States,[nb 1] 175 artists were represented in more than 800 works.

The Société Anonyme's exhibition rooms were too small, but Dreier's attempts to find larger quarters kept breaking down because the funds, which came mainly from her and her two sisters, were insufficient.

In 1916 Dreier helped found the Society of Independent Artists where she met Marcel Duchamp with whom she had a lifelong friendship.

Dreier's health began to decline, having a "crippling illness", about 1942, but she continued to work, giving lectures and writing.

Dreier's major achievement lay neither in her writings nor in her painting, however, but in her early recognition and championship of such artists as Duchamp, and Kandinsky, as well as Klee, Gabo, Villion, Léger and Mondrian, and in her determined attempts to create both an institution and a climate of acceptance for their work.