Arsi Ilari Harju (born March 18, 1974 in Kurikka) is a Finnishshot putter with the team Perhon kiri. He won the gold medal at the 2000 Summer Olympics with a distance of 21.29 metres (69 ft 10 in). His personal best is 21.39, which he put in the qualifiers for the same Olympics. Due to his success in the Olympics and elsewhere that year, Harju was named Finnish Athlete of the Year in 2000.
Harju was the 12th member to be inducted into the 20 metre club after he successfully putted the shot 20.16 m in a competition on March 2, 1997, in Tampere, Finland.
Harju was a patron of UNICEF School walks in Finland.
In 2011, Arsi Harju made a comeback after six years in Tucson, USA. His comeback result was 18.48.