Sten Gustaf Stymne (born 28 November 1949 in Gävle) is a Swedish biochemist and professor emeritus in plant breeding at the Swedish University of Agricultural Sciences.
During the years, Stymne has been one of the leaders in plant lipid biochemistry and was awarded the 2008 Terry Galliard Award as a recognition for his contributions to the field.
Stymne has for many years been a frequent debater in various news media, criticizing Sweden and the European Union for its negative attitude towards plant biotechnology.