Dame Fiona Margaret Powrie DBE FRS FMedSci (born 1963) is currently the head of the Kennedy Institute of Rheumatology at the University of Oxford.

[5] Powrie worked with Don Mason at the Sir William Dunn School of Pathology studying the interactions of different subsets of CD4+ T cells in rats.

Here, she extended her earlier work in rats to mice and developed the "T cell transfer" model, one of the most prominent models of intestinal inflammation where transfer of CD4+CD45RBhi T cells to Rag deficient or SCID mice led to the development of severe intestinal inflammation and wasting disease.

[15] In 2009, Powrie was appointed as the inaugural Sidney Truelove Professor of Gastroenterology within the Nuffield Department of Clinical Medicine in Oxford.

[17] Powrie was appointed Dame Commander of the Order of the British Empire (DBE) in the 2022 Birthday Honours for services to medical science.