Konstantin Vasilyevich Dushenko is a Russian translator, culturologist and historian. His with the Institute of Scientific Information on Social Sciences of the Russian Academy of Sciences. He authored over 30 books on the origins of various quotations, aphorisms, and bon mots.

Konstantin Aleksandrovich Efetov is a Ukrainian biologist and biochemist, Honored Scientist of Ukraine, Academician of the Russian Academy of Natural History, Professor, Dr. Biol. Sci., Head of the Department of Biological Chemistry and Laboratory of Biotechnology of the Crimea State Medical University.

Konstantin Romanovich Eiges was a Russian composer, teacher and pianist.

Konstantin Stepanovich Eremeev was a Russian Bolshevik revolutionary, Soviet military leader, journalist and newspaper editor.

Konstantin Aleksandrovich Fedin was a Soviet and Russian novelist and literary functionary.

Konstantin Petrovich Feoktistov was a Soviet cosmonaut and an eminent space engineer. As a cosmonaut Feoktistov flew on Voskhod 1, the first spacecraft to carry three crew members. Feoktistov also wrote several books on space technology and exploration. The Feoktistov crater on the far side of the Moon is named in his honor.

Konstantin Mikhailovich Fofanov was a Russian poet.

Konstantin Georgiev Fotinov was a Bulgarian writer, translator and enlightener of the Bulgarian National Revival period. The publisher of the first Bulgarian-language magazine, he is regarded as the founder of the Bulgarian press.

Konstantin (Georgiyevich) Mostras was a Russian violinist, teacher and composer.

Konstantin Dmitrievich Glinka (1867–1927) was a Russian soil scientist. He was Director of the Agricultural College of Leningrad and Experimental Station, and the first director of the Dokuchaev Soil Science Institute. He authored over 150 works on soil, geography, mineralogy, and geology. He is known for having published the first world soil map in 1906.