Geoffrey Michael Gadd OBE FRSB FLS FLSW FRSE[1][2] (born 15 July 1954) is a British-Irish microbiologist and mycologist specializing in geomicrobiology, geomycology, and bioremediation.

He also served on the Cell Biology; Physiology and Biochemistry; and Environmental Microbiology Groups and organized several SGM meetings and Main symposia.

Geoffrey Gadd currently holds the Boyd Baxter Chair of Biology at the School of Life Sciences at the University of Dundee [1][2] and leads the Geomicrobiology Group.

[5] Original contributions relate to establishing the field of geomycology within geomicrobiology, and the multidisciplinary research outputs at the interface of microbiology, mineralogy, and geochemistry have greatly furthered understanding of the processes underlying metal and radionuclide accumulation, detoxification and tolerance, mechanisms affecting metal mobility in the environment, mineral dissolution, the formation of biogenic minerals, and biodeterioration of the built environment and cultural heritage.

[7] A recent paper with Marina Fomina and colleagues in Kyiv, Ukraine describes the isolation of a Rhodococcus aetherivorans strain from lubricant-contaminated soil as a prospective phenol biodegrading agent.