Arsi Ilari Harju (born 18 March 1974) is a Finnish former track and field athlete who competed in the shot put.

In the final, Harju secured the gold medal with his second round shot put of 21.29, beating silver medalist Adam Nelson by 8 cm and bronze medalist John Godina by 9 cm.

In 2000, Harju was also named the Finnish Sports Personality of the Year.

Harju was the 12th member to be inducted into the 20 metre club after achieving the distance of 20.16 on 2 March 1997, in Tampere, Finland.

Harju was a patron of UNICEF School walks in Finland.