Karl E. Linderfelt (November 7, 1876 – June 3, 1957) was a soldier, mine worker, soldier of fortune, and officer in the Colorado National Guard. He was reported to have been responsible for an attack upon, and the ultimate death of, strike leader Louis Tikas during the Ludlow Massacre. He was the son of librarian Klas August Linderfelt. Most of what is known from Linderfelt's life is from a congressional testimony after the events at Ludlow.