Fiona Watt, FRS FMedSci (born 28 March 1956) is a British scientist who is internationally known for her contributions to the field of stem cell biology.

She also obtained her Doctor of Philosophy degree from the Sir William Dunn School of Pathology, University of Oxford in 1979, supervised by Henry Harris with a thesis on Microtubule-organizing centres in cells in culture and in hybrids derived from them'.

Upon returning to the UK, she founded her first lab at the Kennedy Institute of Rheumatology in London where she became Head of the Molecular Cell Biology Laboratory.

Watt’s major research contribution has been to elucidate how the outer covering of mammalian skin, the epidermis, is maintained through self-renewal of stem cells and terminal differentiation of their progeny.

Using cultured human epidermis and genetically modified mice, she pioneered the identification of stem cell populations and elucidated the roles of integrin,[8] Notch,[9] Wnt[10] and receptor tyrosine kinase[11] signalling in regulating their behavior.

By demonstrating the existence of functionally distinct skin fibroblast lineages[17] she has opened the way for new strategies to treat scarring and fibrosis.

[22] Watt has played a key role in promoting UK government investment in stem cell research, for example, as specialist adviser to the House of Lords Science and Technology Committee.

In 2020, Watt spearheaded efforts to fund coronavirus research, helping to ensure that the first awards from UKRI/DHSC were made just as the scale of the pandemic was becoming apparent.

[29][30] In December 2020 a whistleblowing investigation was triggered by UK Research and Innovation (UKRI), determining that Watt had acted in a bullying manner.

[31][32] Watt remained in post until her term as MRC Executive Chair ended in early 2022, then took up her new position as director of the European Molecular Biology Organization.