Martti Bertil Marttelin (18 June 1897 – 1 March 1940) was a long-distance runner from Finland, who competed at the 1928 Summer Olympics.
Marttelin won the bronze medal in the men's marathon at the 1928 Summer Olympics.
Marttelin finished second behind Dunky Wright in the marathon event at the British 1930 AAA Championships.
He was killed in action during World War II.
Martti B. Marttelin at Olympics.comMartti Marttelin at Olympic.org (archived)
Martti Marttelin at World Athletics