Dorothy "Dottie" Thomas (née Martin) (September 18, 1922 – January 9, 2015) was an American hematology researcher and administrator known for her work in developing bone marrow transplants. She and her husband, E. Donnall Thomas (Don), partnered to research leukemia and other blood disorders, and developed the technique for transplanting bone marrow.
Thomas was born and raised in Texas, attending public school in her hometown of San Antonio throughout her childhood. She studied journalism at the University of Texas at Austin.
Thomas decided to switch to medicine and moved to New England Deaconess Hospital, where she qualified as a hematology technician. Thomas graduated from medical technology training in the 1940s and worked as a technician for other physicians while her husband completed his degree and got his laboratory. Thomas worked part time in her husband's lab while their children were young. In the 1950s, Don became physician-in-chief at Mary Imogene Bassett Hospital in New York, and the work on bone marrow transplant began. In 1963 they moved to Seattle and continued their research at the University of Washington School of Medicine. They conducted research together at Seattle's Fred Hutchinson Cancer Research Center beginning in 1975, when it was founded and where she was, for fifteen years, chief administrator of the clinical research division, of which Don was the director.
When Donnall Thomas was awarded a Nobel Prize in 1990 for the couple's work, he responded "I'm pleased for my wife and for me and for my team and for the cancer center."
George Santos, a transplant specialist, remarked that if Don was considered the father of bone marrow transplants, "then Dottie Thomas is the mother".
Thomas began an endowment at the Fred Hutchinson Center in 2014 called Dottie's Bridge, intended to support young researchers with fellowships.