Guglielmo Ferrero was an Italian historian, journalist and novelist, author of the Greatness and Decline of Rome. Ferrero devoted his writings to classical liberalism and he opposed any kind of dictatorship and unlimited government.

Guillaume Apollinaire was a French poet, playwright, short story writer, novelist, and art critic of Polish descent.

Gunnar Gunnarsson was an Icelandic author who wrote mainly in Danish. He grew up, in considerable poverty, on Valþjófsstaður in Fljótsdalur valley and on Ljótsstaðir in Vopnafjörður. During the first half of 20th century he became one of the most popular novelists in Denmark and Germany. One time he went to Germany and had a meeting with Hitler and is considered to be the only Icelander to have met him.

Gunther Plüschow was a German aviator, aerial explorer, and author from Munich, Bavaria. His feats include the only escape by a German prisoner of war in either world war from Britain back to Germany; he was the first man to explore and film Tierra del Fuego and Patagonia from the air. He was killed on a second aerial expedition to Patagonia in 1931. As an aviator and explorer, he is honored as a hero by the Argentine Air Force to this day.

Gustav Theodor Fechner was a German physicist, philosopher, and experimental psychologist. A pioneer in experimental psychology and founder of psychophysics, he inspired many 20th-century scientists and philosophers. He is also credited with demonstrating the non-linear relationship between psychological sensation and the physical intensity of a stimulus via the formula: , which became known as the Weber–Fechner law.

Gustav Freytag was a German novelist and playwright.

Gustav Karpeles (11 November 1848 in Ivanovice na Hané, Margraviate of Moravia – 21 July 1909 in Nauheim) was a German Jewish historian of literature and editor; son of Elijah Karpeles.

Gustave Aimard was the author of numerous books about Latin America and the American frontier.

Gustave Flaubert was a French novelist. He has been considered the leading exponent of literary realism in his country and abroad. According to the literary theorist Cornelius Quassus, "in Flaubert, realism strives for formal perfection, so the presentation of reality tends to be neutral, emphasizing the values and importance of style as an objective method of presenting reality". He is known especially for his debut novel Madame Bovary (1857), his Correspondence, and his scrupulous devotion to his style and aesthetics. The celebrated short story writer Guy de Maupassant was a protégé of Flaubert.

Charles-Marie Gustave Le Bon was a leading French polymath whose areas of interest included anthropology, psychology, sociology, medicine, invention, and physics. He is best known for his 1895 work The Crowd: A Study of the Popular Mind, which is considered one of the seminal works of crowd psychology.