Joan Mitchell (February 12, 1925 – October 30, 1992) was an American artist who worked primarily in painting and printmaking, and also used pastel and made other works on paper. She was an active participant in the New York School of artists in the 1950s. A native of Chicago, she is associated with the American abstract expressionist movement, even though she lived in France for much of her career.

Mitchell's emotionally intense style and its gestural brushwork were influenced by nineteenth-century post-impressionist painters, particularly Henri Matisse. Memories of landscapes inspired her compositions; she famously told art critic Irving Sandler, "I carry my landscapes around with me." Her later work was informed and constrained by her declining health.

Mitchell was one of her era's few female painters to gain critical and public acclaim. Her paintings, drawings, and editioned prints can be seen in major museums and collections around the world, and have sold for record-breaking prices. In 2021, the San Francisco Museum of Modern Art and Baltimore Museum of Art co-organized a comprehensive retrospective of her work. The Fondation Louis Vuitton presented an exhibition of the work of Mitchell and Claude Monet from October 2022 to February 2023.

In her will, Mitchell provided for the creation of the Joan Mitchell Foundation, a non-profit corporation that awards grants and fellowships to working artists and maintains her archives.

Mitchell's family roots trace back to the Revolutionary War. The dust jacket front inside flap of Joan Mitchell Lady Painter: A Life describes Mitchell as an heiress. Her mother, Marion Strobel is described as an heiress, while her father, Dr. James Herbert Mitchell was an "unpedigreed son of a downstate farmer". They married on December 6, 1922, on North Michigan Avenue.

In 1857, Sarah Moore and Daniel Baxter, Marion's maternal grandparents, left "well-established" Quincy, Massachusetts families to settle on Ohio Street in Chicago. By 1871, Daniel Baxter had accumulated $100,000 ($2.6 million in 2024) in the grain business. Joan's grandmother, Henrietta Baxter, was the eldest of their five children. In 1890, Henrietta married Cincinnati-bred Charles Louis Strobel. Strobel was the son of pocketbook factory owner and immigrant, Karl Strobel, and a descendant of Bavarian porcelain merchants. A trained civil engineer, Charles worked for 27 years at Andrew Carnegie's Keystone Bridge Company.

James Herbert Mitchell is from Havana, Illinois where his maternal grandparents, George and Waity Vaugahan had moved to from Vermont in 1839. With a 177 acres (0.277 sq mi) land grant signed by President James Polk they built a farmhouse and raised corn, wheat, horses, sheep and dairy cows. Their ancestors had been British colonists and tannery operators. Joan was known to make claims that her paternal great-grandfather was an American Revolution combatant. These claims were not confirmed. Sarah Felicia Vaughan married a Mr. James Hickman Herndon Mitchell in 1873, having outsurvived both of her brothers and mother. Her sickly father passed in 1874. Mitchell was the youngest of 11 children born to Isaac Mitchell and Frances Stribling Mitchell who had left Virginia to homestead in Kentucky and then along the Illinois River. Her half great-uncle (Jim H. H. Mitchell's half brother), Henry Harrison Mitchell, was the first casualty of his county in the American Civil War.

Mitchell was born in Chicago, Illinois, the daughter of dermatologist James Herbert Mitchell and poet Marion Strobel Mitchell. Her father served as president of the American Dermatological Association, her mother served as co-editor of Poetry. She enjoyed diving and skating growing up, and her art would later reflect this athleticism; one gallery owner commented that Mitchell "approached painting almost like a competitive sport". Mitchell frequently attended Saturday art classes at the Art Institute of Chicago, and eventually would spend her summers of later adolescence in an Institute-run art colony, Ox-Bow. She lived on Chestnut Street in the Streeterville neighborhood and attended high school at Francis W. Parker School in the Lincoln Park neighborhood. She was close to her Parker classmate Edward Gorey and remained friends with him in later years, although neither cared for the other's work. When her maternal grandfather, Charles Louis Strobel, died in April 1936, her inheritance was two-thirds of his $500,000 ($11.3 million in 2024), and she would later inherit trusts from both parents.