Gustav Kalkun (22 March 1898 – 24 April 1972) was an Estonian discus thrower.^[3] He competed at the 1924 and 1928 Olympics and placed 15th and 10th, respectively.^[1] He was selected as the Olympic flag bearer for Estonia in 1928.^[4][5]

Kalkun graduated from school in Riga, Latvia (1916), and then studied physical education in Tartu, Estonia (1927), and Geneva, Switzerland (1930). He fought as a volunteer in World War I and Estonian War of Independence. He later worked as a physical education teacher in Tallinn, Narva and Tartu and acted as a referee and journalist covering athletics and basketball. In 1944, when Soviet troops arrived in Estonia, he emigrated to the United States.^[6] He was physical director of the YMCA in London, Ontario until 1950, when he took the same position at the YMCA in Sault Ste. Marie, Ontario.^[3] He was married to Waralda Ilmatara Kalkun, who died in 1967.^[7] Kalkun died at a hospital in Windsor, Ontario, in 1972.^[8]

Kalkun's nephew was actor Karl Kalkun, whose son is the sports journalist Kristjan Kalkun [et].^[9]