There were seven children in Georgia O'Keeffe's family, including Georgia herself.
O'Keeffe was the second of seven children born to Francis Calyxtus O'Keeffe and Ida Totto O'Keeffe. She grew up on a dairy farm near Sun Prairie, Wisconsin, in a large family whose rural setting became part of her early life story.
Her childhood education included art lessons, and she decided while still young that she would become an artist. She later attended the School of the Art Institute of Chicago and the Art Students League in New York before working as an art teacher. Those early stages preceded the abstract drawings that brought her to the attention of Alfred Stieglitz.
A common mix-up is to confuse the number of O'Keeffe children with the number of siblings she had. Because she was one of seven children, she had six siblings. The answer to this question counts Georgia herself, not just the brothers and sisters around her.