Deborah Doniach (née Abileah; 6 April 1912 – 1 January 2004) was a British clinical immunologist and pioneer in the field of autoimmune diseases.

Due to the frequent moves and her parents' bohemian lifestyle, she did not start any formal education until the age of nine, when she and her sisters were staying at an Italian convent while her mother was recovering from tuberculosis at a sanitorium and her father was accompanying the violinist Josef Szigeti on a tour of the United States.

[1][8] Her observation of patients with Hashimoto's disease and knowledge of the field led her to realise that excess antibodies were an autoimmune reaction against the thyroid gland itself rather than external microbes.

[1][5] She collaborated with Ivan Roitt and Peter Campbell to further understand the autoimmune basis of Hashimoto's disease (citations).

Doniach continued her studies at Middlesex Hospital with various collaborators, including Roitt, Sheila Sherlock, Keith Taylor, and Gian Franco Bottazzo, and uncovered an autoimmune basis for numerous diseases, including pernicious anemia, primary biliary cirrhosis, and type I diabetes [1][5] This led to the concept of organ-specific auto-immunity.