Bjørn Grimnes (born 24 September 1950) is a former javelin thrower from Norway. He represented Kongsberg IF.

At the 1972 Summer Olympics, he finished fifth in the javelin final with a throw of 83.08 metres. At the 1976 Summer Olympics, he finished fourteenth with 74.88 m.[1] He became Norwegian champion in 1972, 1973 and 1978.[2]

His personal best throw was 88.32 metres (old type), achieved in June 1978 in Helsinki.[3]