John Fenn, American chemist and academic, Nobel Prize laureate (died 2010)

John Bennett Fenn was an American professor of analytical chemistry who was awarded a share of the Nobel Prize in Chemistry in 2002. He shared half of the award with Koichi Tanaka for their work in mass spectrometry. The other half went to Kurt Wüthrich. Fenn's contributions specifically related to the development of electrospray ionization, now a commonly used technique for large molecules and routine liquid chromatography-tandem mass spectrometry. Early in his career, he studied the field of jet propulsion at Project SQUID and focused on molecular beams. He finished his career with more than 100 publications, including one book.

The Nobel Prize in Chemistry is awarded annually by the Royal Swedish Academy of Sciences to scientists in the various fields of chemistry. It is one of the five Nobel Prizes established by the will of Alfred Nobel in 1895, awarded for outstanding contributions in chemistry, physics, literature, peace, and physiology or medicine. This award is administered by the Nobel Foundation and awarded by the Royal Swedish Academy of Sciences on proposal of the Nobel Committee for Chemistry, which consists of five members elected by the Academy. The award is presented in Stockholm at an annual ceremony on December 10th, the anniversary of Nobel's death.