Kenneth Sverre Hagen (26 November 1919 – 10 January 1997) was an American professor of entomology at the University of California, Berkeley who was a specialist on the predators of sucking pests such as psyllids and aphids.
He worked on approaches to integrated pest management based on the augmentation of natural predators and parasites and in the use of nutrient sprays to encourage them.
He obtained a BS in 1943 but his studies were interrupted by service as a naval officer in the second world war.
After obtaining his Ph.D. under Richard Doutt in 1952 he became a junior entomologist at the experimental station in Albany.
He studied the migration of Hippodamia convergens, making use of hot-air balloons.