Mark George Tobey (December 11, 1890 – April 24, 1976) was an American painter. His densely structured compositions, inspired by Asian calligraphy, resemble Abstract expressionism, although the motives for his compositions differ philosophically from most Abstract Expressionist painters. His work was widely recognized throughout the United States and Europe. Along with Guy Anderson, Kenneth Callahan, Morris Graves, and William Cumming, Tobey was a founder of the Northwest School. Senior in age and experience, he had a strong influence on the others; friend and mentor, Tobey shared their interest in philosophy and Eastern religions. Similar to others of the Northwest School, Tobey was mostly self-taught after early studies at the Art Institute of Chicago. In 1921, Tobey founded the art department at The Cornish School in Seattle, Washington.

Tobey was an incessant traveler, visiting Mexico, Europe, Palestine, Israel, Turkey, Lebanon, China, and Japan. After converting to the Baháʼí Faith, it became an important part of his life. Whether Tobey's all-over paintings, marked by oriental brushwork and calligraphic strokes, were an influence on Jackson Pollock's drip paintings has been left unanswered. Born in Centerville, Wisconsin, Tobey lived in the Seattle, Washington area for most of his life before moving to Basel, Switzerland in the early 1960s with his companion, Pehr Hallsten; Tobey died there in 1976.

Tobey was the youngest of four children in a Congregationalist family. His parents were George Tobey, a carpenter and house builder, and Emma Cleveland Tobey. The father carved animals from stone and sometimes drew animals for young Mark to cut out with scissors. In 1893, the family settled in Chicago. He studied at the Art Institute of Chicago from 1906 to 1908, but, like others of the Northwest School, was mostly self-taught. In 1911, he moved to New York City where he worked as a fashion illustrator for McCall's. His first one-man show was held at Knoedler & Company in lower Manhattan, in 1917. The following year, Tobey came in contact with New York portrait artist and Baháʼí Juliet Thompson—an associate of Khalil Gibran—and posed for her. During the session, Tobey read some Baháʼí literature and accepted an invitation to Green Acre where he converted to the Baháʼí Faith. His conversion led him to explore the representation of the spiritual in art. In the following years, Tobey delved into works of Arabian literature and teachings of East Asian philosophy.

Tobey's arrival in Seattle in 1921 was in part an effort for a new start following a marriage and quick divorce. When his ex-wife found Tobey's address, she sent him a box of his clothes topped with a copy of Rudyard Kipling's The Light That Failed. In the following year, Tobey met Teng Kuei, a Chinese painter and student at the University of Washington, who introduced Tobey to Eastern penmanship, beginning Tobey's exploration of Chinese calligraphy. The beginning of his lifelong travels occurred in 1925 when he left for Europe, settling in Paris where Tobey met Gertrude Stein. He spent a winter at Châteaudun, and also traveled to Barcelona and Greece. In Constantinople, Beirut and Haifa, he studied Arab and Persian writing.

Upon returning to Seattle in 1927, Tobey shared a studio in a house near the Cornish School (with which he was intermittently associated) with the teenage artist, Robert Bruce Inverarity, who was 20 years younger. Inspired by Inverarity's high-school project, Tobey developed interest in three-dimensional form and carved some 100 pieces of soap sculpture. The next year, Tobey co-founded the Free and Creative Art School in Seattle with Edgar Ames, and in autumn, he taught an advanced art course at Emily Carr's Victoria studio.

In 1929, he participated in a show that marked a change in his life: a solo exhibition at Romany Marie's Cafe Gallery in New York. Alfred H. Barr, Jr., then a curator at the Museum of Modern Art (MoMA), saw the show and selected several pictures from it for inclusion in MoMA's 1930 exhibition: Painting and Sculpture by Living Americans. In 1931, Tobey became a resident artist of the Elmhurst Progressive School while teaching at Dartington Hall in Devon and painting frescoes for the school. He became a close friend of Bernard Leach, who was also on the faculty. Introduced by Tobey to the Baháʼí Faith, Leach became a convert. During his stay in Devon, Tobey found time to travel to Mexico (1931), Europe, and Palestine (1932). In 1934, Tobey and Leach traveled together through France and Italy, then sailed from Naples to Hong Kong and Shanghai, where they parted company. Leach went on to Japan, while Tobey remained in Shanghai visiting his old friend, Teng Kuei, before departing for Japan. Japanese authorities confiscated and destroyed an edition of 31 drawings on wet paper that Tobey had brought with him from England to be published in Japan. No explanation for their destruction has been noted; possibly they considered his sketches of nude men pornographic. In early summer, he studied Haiku poetry and calligraphy at a Zen monastery outside Kyoto before returning to Seattle in autumn.

Tobey's first solo exhibition at the Seattle Art Museum occurred in 1935; he also traveled to New York, Washington, D.C., Alberta, Canada, as well as Haifa for a Baháʼí pilgrimage. Sometime in November or December, while working at night at Dartington Hall and listening to the horses breathe in the field outside his window, he painted a series of three paintings, Broadway, Welcome Hero, and Broadway Norm, in the style that would become known as "white writing" (an interlacing of fine white lines).

Tobey expected to return to teaching in England in 1938, but the mounting tensions of war building in Europe kept him in the US. Instead, he began to work on the Federal Art Project, under the supervision of Inverarity. In June 1939, when Tobey attended a Baháʼí summer program and overstayed his allotted vacation time, Inverarity dropped him from the Works Progress Administration (WPA) project. Tobey met the Swedish scholar, Pehr Hallsten (died 1965, Basel), in Ballard in 1939 and they became companions, living together from 1940. By 1942, Tobey's process of abstractionism was accompanied by a new calligraphic experiment. Marian Willard of the Willard Gallery in New York had seen some of Tobey's WPA paintings and gave him a show in 1944, which was considered to be a major success. In 1945, he gave a solo exhibition at the Portland Art Museum in Oregon, and the Arts Club of Chicago held solo shows of his work in 1940 and 1946. He studied the piano and the theory of music with Lockrem Johnson, and, when Johnson was away, with Wesley Wehr, who was introduced to Tobey in 1949 by their pianist friend Berthe Poncy Jacobson. Wehr, an undergraduate at the time, happily accepted the opportunity to serve as a stand-in music composition tutor for Tobey and over time became friends with him and his circle of artists, becoming a painter himself, as well as a chronicler of the group.