Gustav Heinrich Otth (2 June 1806, in Bern – 8 November 1874) was a Swiss mycologist and military officer.
[1] He was the brother of naturalist Carl Adolf Otth (1803–1839).
[2] Known for his taxonomic research, Otth described Pucciniastrum,[3] a genus of rust fungi within the family Pucciniastraceae.
[4] He was the binomial author of a number of species within the genus Peronospora.
[5] The fungi genus Otthia (Nitschke ex Fuckel) was named in his honour in 1870.