Gustav Kalkun (22 March 1898 – 24 April 1972) was an Estonian discus thrower.

[4][5] Kalkun graduated from school in Riga, Latvia (1916), and then studied physical education in Tartu, Estonia (1927), and Geneva, Switzerland (1930).

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.

This biographical article relating to Estonian athletics is a stub.