G
- Johan Gadolin, Finnish chemist and geologist — gadolinite, the mineral after which the chemical element gadolinium has been named
- Thomas Gage (botanist) — greengage
- Uziel Gal — the Uzi submachine gun
- Galileo Galilei — galileo or gal, unit of acceleration
- Israel Galili — the Galil assault rifle
- Luigi Galvani (1737–1798), discovered the Galvanic response of muscles to electricity. The process of galvanization is also named after him.
- James Gamble and William Procter — Procter & Gamble
- Henry Laurence Gantt — Gantt chart
- John Garand — M1 Garand rifle
- Alexander Garden (naturalist) - after whom the gardenia was named.
- Giuseppe Garibaldi — Garibaldi biscuits, Italian aircraft carrier Giuseppe Garibaldi
- Gideon Gartner — Gartner
- Hermann Gartner — Gartner's duct
- Richard J. Gatling — Gatling gun
- Carl Friedrich Gauss — gauss — unit of magnetic induction, Gauss' law; see also: List of topics named after Carl Friedrich Gauss.
- Enola Gay Tibbets — Enola Gay, the plane that dropped the first atomic bomb. Tibbets' son Paul Tibbets, pilot of the plane, named it after his mother.
- Joseph Louis Gay-Lussac and Jacques Charles — Law of Charles and Gay-Lussac
- Lou Gehrig, American Baseball player — Lou Gehrig's Disease
- Hans Geiger — Geiger counter, Geiger-Müller tube
- King George I of Great Britain — Georgia (U.S. state)
- King George VI of Great Britain — George Cross
- Elbridge Gerry - gerrymandering
- Domingo Ghirardelli — Ghirardelli Chocolate Company
- Josiah Willard Gibbs — Gibbs free energy, Gibbs phenomenon
- Thomas Gilbert — Kiribati
- King Camp Gillette - founder, Gillette
- Gaston Glock — GLOCK GmbH and its best-known product, the Glock pistol
- Kurt Gödel — Gödel's incompleteness theorem, Gödel's ontological proof
- Maria Goeppert-Mayer - Goeppert-Mayer (GM) unit for the cross section of two-photon absorption
- Samuel Goldwyn — Goldwyn Picture Corporation, later merged into Metro-Goldwyn-Mayer Inc. (or MGM)
- Wilbert Gore — Gore-Tex
- Klement Gottwald — Zlín, a city in Moravia, the Czech Republic, was renamed Gottwaldov during 1949—1990.
- Ernst Gräfenberg — Gräfenberg spot (G-spot)
- Sylvester Graham — Graham crackers, Graham flour
- Thomas Graham — Graham's Law
- Robert James Graves — Graves-Basedow disease
- Louis Harold Gray — gray, unit of absorbed dose of radiation
- Henri Grob — Grob's Attack
- Ernst Grünfeld — Grünfeld Defence
- Vicente Guerrero — Guerrero
- Georges Guillain — Guillain-Barré syndrome
- Dr. Joseph Ignace Guillotin (1738–1814) — advocate of what came to be called the guillotine
- Henry C. Gunning — mineral Gunningite
- Robert John Lechmere Guppy (1836–1916) — Guppy or guppie
Read more about this topic: List Of Eponyms (A-K)