Gustav Ranis was a leading development economist and the Frank Altschul Professor Emeritus of International Economics at Yale University.

Gustav Regler (25 May 1898 – 14 January 1963) was a German writer and journalist.

Gustav Benjamin Schwab was a German writer, pastor and publisher.

Gustav Seyffarth was a German-American Egyptologist, born in Uebigau, in the Electorate of Saxony.

Gustav Gustavovich Shpet was a Russian philosopher, historian of philosophy, psychologist, art theoretician, and interpreter of German-Polish descent.

Gustav Spiller was a Hungarian-born ethical and sociological writer who was active in Ethical Societies in the United Kingdom. He helped to organize the First Universal Races Congress in 1911.

Gustav Storm was a Norwegian historian, a professor at the Royal Frederick University in Christiania from 1877. He was a driving force in the research of Scandinavian history and literature of the Middle Ages.

Gustav Struve, known as Gustav von Struve until he gave up his title, was a German surgeon, politician, lawyer and publicist, and a revolutionary during the German revolutions of 1848–1849 in Baden, Germany. He also spent over a decade in the United States and was active there as a reformer.

Gustav Suits is considered one of the greatest Estonian poets. He was also an early leader of the literary movement group Noor-Eesti.

Gustav Teichmüller was a German philosopher. His works, particularly his notion of perspectivism, influenced Friedrich Nietzsche's philosophy.