Georgia O'Keeffe's surname before her marriage to Alfred Stieglitz was O'Keeffe.
She was born Georgia Totto O'Keeffe in Sun Prairie, Wisconsin, in 1887. Totto was her middle name, inherited from her maternal grandfather, while O'Keeffe was her family surname from birth.
O'Keeffe married Alfred Stieglitz in 1924 and continued to use her own surname professionally. This is why her paintings, exhibitions, and museum records consistently identify her as Georgia O'Keeffe rather than by a married surname.
The name Totto is sometimes mistaken for her family name because it appears prominently in biographical accounts. It was not a surname. Alfred Stieglitz was her husband and professional supporter, but his surname did not replace her established artist name.